From Newsgroup: alt.os.linux.mint


It's become very difficult nowadays to buy new hard drives using CMR technology for normal desktop use
--
Linux Mint 22.2
{I shot Felix and buried him}

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From Newsgroup: alt.os.linux.mint

On Wed, 24 Dec 2025 15:30:38 +1100, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR technology for normal desktop use

I got a new 12TB drive for my backup machine just a couple months ago.
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From Newsgroup: alt.os.linux.mint

Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 15:30:38 +1100, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR
technology for normal desktop use

I got a new 12TB drive for my backup machine just a couple months ago.

I don't use any that large. I'm finding most drives above 1Tb are SMR though
--
Linux Mint 22.2
{I shot Felix and buried him}

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From Newsgroup: alt.os.linux.mint

Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR technology for normal desktop use

Try WD Purple, you can get a 2TB CMR
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From Newsgroup: alt.os.linux.mint

On Wed, 24 Dec 2025 16:38:33 +1100, Axel wrote:

Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 15:30:38 +1100, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR
technology for normal desktop use

I got a new 12TB drive for my backup machine just a couple months ago.

I'm finding most drives above 1Tb are SMR though

This one is a Seagate IronWolf NAS drive.
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From Newsgroup: alt.os.linux.mint

On 24/12/2025 3:33 pm, Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 15:30:38 +1100, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR
technology for normal desktop use

I got a new 12TB drive for my backup machine just a couple months ago.

That's a lot of eggs in one basket, personally I'd prefer a RAID 5 or 6
setup with smaller drives.
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.mint

On 12/24/25 1:14 AM, Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 16:38:33 +1100, Axel wrote:

Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 15:30:38 +1100, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR
technology for normal desktop use

I got a new 12TB drive for my backup machine just a couple months ago.

I'm finding most drives above 1Tb are SMR though

This one is a Seagate IronWolf NAS drive.

like this? https://www.amazon.com/dp/B084ZV4DXB?th=1
--
Linux Mint 22.2, Mozilla Thunderbird 140.6.0esr, Mozilla Firefox 146.0.1
Alan K.
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From Newsgroup: alt.os.linux.mint

On Tue, 12/23/2025 11:30 PM, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR technology for normal desktop use

https://www.seagate.com/ca/en/products/cmr-smr-list/

# Makes it pretty clear which ones to avoid

The situation here, is more sketchy.

https://www.reddit.com/r/DataHoarder/comments/1jjt6g3/western_digital_cmrsmr_lists_reliable/

WD Red, Blue, Purple, Gold and WD_BLACK Drives

WD Gold 3.5" - all CMR <=== good, but pricey (may state Helium or Air)

WD_BLACK 3.5" - all CMR <=== some of these are good, try an 8TB one (air breather)
They may not be making 6TB any more. Same platter count, 8TB capacity.
The Helium cannot run out of this one, as this one is air.

WD Blue 3.5" - ignore - depends on size... [download datasheet and check]
CMR WD60EZAX WD40EZAX WD30EZAX
SMR WD60EZAZ WD40EZAZ WD30EZAZ (peaks into Best Buy lock room...)
Larger are CMR, all are air breathers (even 12TB one)

WD Purple Pro 3.5" - all CMR \
\___ Surveillance cam, multi-thread write
WD Purple 3.5" - All CMR /

WD Red Plus 3.5" - All CMR <=== No idea what the intended purpose of these is
Maybe they are whatever the "WD Red" was supposed to be.

WD Red 3.5" - All SMR <=== Name ruined by bad publicity and dishonesty

WD Red Pro 3.5" - All CMR <=== Presumably for NAS

*******

WD Black 2.5" - ignore - depends on size

WD Blue 2.5" - All SMR

WD Red 2.5" (CMR) - no link, but looks like they are all CMR

*******

The HAMR ones are all CMR at the moment, presumably because a
zero clearance shingle would not mix with waving a laser around in there.
The laser might heat up an adjacent track and make the edge of the
track easier to write with a weak field.

*******

Summary: "Cheap" drives in CMR might be harder to find (company stocks the Z ones instead)
You have to be careful in the lowest tier (Barracuda or WD Blue Z)

The drives being flogged by Tomshardware, might not have passed
some certification which is why they sell at half price. We don't
know the back-story of such drives, where they came from, how it
was necessary to "dump them in external enclosures for a song".
The pricing going on, is not all Sparkle Ponies.

You might find used Chia Pets on Ebay, that have been refurbed and
reset by the unscrupulous. You cannot go to bazaar sites and always
get a good deal. You cannot "squeeze the produce" and spot the
rotten ones.

It's quite the business model, the "anonymous bag of bits" model.

Out of all the drives I've bought, I only ever had one "infant mortality".
I bought a WD Black 1TB two years ago, the motor was dead. Since drives
are 100% tested, how did that drive "fall off the production line" ?
The tech in the builder-section at the computer store, was also
surprised when he tested it on his rig and he refunded me. It's OK
for a drive to wear out prematurely due to bad design, it's quite
another for one to not work at T=0. But it happens I guess.

Paul

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.mint

On Wed, 24 Dec 2025 21:18:19 +1000, keithr0 wrote:

On 24/12/2025 3:33 pm, Lawrence DrCOOliveiro wrote:

I got a new 12TB drive for my backup machine just a couple months
ago.

That's a lot of eggs in one basket ...

ThatrCOs why I have a backup machine.

... personally I'd prefer a RAID 5 or 6 setup with smaller drives.

RAID is about high availability, not about backup.
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.mint

On 2025-12-24, Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:

On Wed, 24 Dec 2025 16:38:33 +1100, Axel wrote:

Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 15:30:38 +1100, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR
technology for normal desktop use

I got a new 12TB drive for my backup machine just a couple months ago.

I'm finding most drives above 1Tb are SMR though

This one is a Seagate IronWolf NAS drive.

CMR drives cost more to maufacture so to get the competitive edge they
produce SMR.

NAS drives require CMR as SMR drives perform poorly.

So buy a HDD for a NAS and it will probably be CMR. Of course due dilegence
is worth your time.
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.mint

Paul wrote:

On Tue, 12/23/2025 11:30 PM, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR technology for normal desktop use

https://www.seagate.com/ca/en/products/cmr-smr-list/

# Makes it pretty clear which ones to avoid

The situation here, is more sketchy.

https://www.reddit.com/r/DataHoarder/comments/1jjt6g3/western_digital_cmrsmr_lists_reliable/

WD Red, Blue, Purple, Gold and WD_BLACK Drives

WD Gold 3.5" - all CMR <=== good, but pricey (may state Helium or Air)

WD_BLACK 3.5" - all CMR <=== some of these are good, try an 8TB one (air breather)
They may not be making 6TB any more. Same platter count, 8TB capacity.
The Helium cannot run out of this one, as this one is air.

WD Blue 3.5" - ignore - depends on size... [download datasheet and check]
CMR WD60EZAX WD40EZAX WD30EZAX
SMR WD60EZAZ WD40EZAZ WD30EZAZ (peaks into Best Buy lock room...)
Larger are CMR, all are air breathers (even 12TB one)

WD Purple Pro 3.5" - all CMR \
\___ Surveillance cam, multi-thread write
WD Purple 3.5" - All CMR /

WD Red Plus 3.5" - All CMR <=== No idea what the intended purpose of these is
Maybe they are whatever the "WD Red" was supposed to be.

WD Red 3.5" - All SMR <=== Name ruined by bad publicity and dishonesty

WD Red Pro 3.5" - All CMR <=== Presumably for NAS

*******

WD Black 2.5" - ignore - depends on size

WD Blue 2.5" - All SMR

WD Red 2.5" (CMR) - no link, but looks like they are all CMR

*******

The HAMR ones are all CMR at the moment, presumably because a
zero clearance shingle would not mix with waving a laser around in there.
The laser might heat up an adjacent track and make the edge of the
track easier to write with a weak field.

*******

Summary: "Cheap" drives in CMR might be harder to find (company stocks the Z ones instead)
You have to be careful in the lowest tier (Barracuda or WD Blue Z)

The drives being flogged by Tomshardware, might not have passed
some certification which is why they sell at half price. We don't
know the back-story of such drives, where they came from, how it
was necessary to "dump them in external enclosures for a song".
The pricing going on, is not all Sparkle Ponies.

You might find used Chia Pets on Ebay, that have been refurbed and
reset by the unscrupulous. You cannot go to bazaar sites and always
get a good deal. You cannot "squeeze the produce" and spot the
rotten ones.

It's quite the business model, the "anonymous bag of bits" model.

Out of all the drives I've bought, I only ever had one "infant mortality".
I bought a WD Black 1TB two years ago, the motor was dead. Since drives
are 100% tested, how did that drive "fall off the production line" ?
The tech in the builder-section at the computer store, was also
surprised when he tested it on his rig and he refunded me. It's OK
for a drive to wear out prematurely due to bad design, it's quite
another for one to not work at T=0. But it happens I guess.

thanks for this. I've been checking on drives too myself. problem is not
all makes/models are stocked by computer shops, and I don't want to
spend a lot. I have been re-purposing what I have here to free up a 1Tb
drive, but if I need to buy a new drive, do you think SMR would be Ok
for desktop use, and/or data storage, or should I only buy CMR?

Paul

--
Linux Mint 22.2
{I shot Felix and buried him}

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From Newsgroup: alt.os.linux.mint

On Sat, 12/27/2025 6:54 AM, Axel wrote:

thanks for this. I've been checking on drives too myself. problem is not
all makes/models are stocked by computer shops, and I don't want to spend a lot.
I have been re-purposing what I have here to free up a 1Tb drive, but if I need
to buy a new drive, do you think SMR would be Ok for desktop use, and/or data storage, or should I only buy CMR?

I consider the SMR to be fine for sequential backups.

1) I would not intentionally buy SMR.

The first generation, as reviewed on Anandtech, dropped to as low as
25MB/sec or so. The SMR drive caching policy is a lot better now than
it was back then, but still, writing seven tracks and having to do
read-modify-write to change a sector within the seven track cluster,
that is just a "crazy thing to do". For me, buying an SMR is like
agreeing to buy a car with square wheels on it.

2) If I had to buy one SMR, I would buy two of them and alternate
the storage on them. Or otherwise use a redundant storage
pattern (put valuable things on two of the drives).

3) With a CMR drive, I am less fearful of the unknown. But HDD are still HDD.
They're not SSD or NVMe, so you know their limits. If you write a program
to shake the head assembly back and forth, 24 hours a day, the arm lasts
about a year doing that (for any HDD). Most desktop usage patterns are
nowhere near that bad. On a desktop there are long periods of idleness.

And when I refer to used drives from the Chia era, the hard drives
were abused to support this project. At one time, this causes a shortage
of hard drives, because the manufacturing could not keep up with demand.
Later, the Chia People were dumping the worn drives and trying to fool people into thinking they were new drives. The Chia interval caused my computer store to lose confidence in the HDD market (they were losing money on "buying high, selling low"), and one day here, they even had an
inventory level of *zero* HDD. Today, they have some again.

( https://en.wikipedia.org/wiki/Chia_Network # Abuse HDD for money )

Paul

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From Newsgroup: alt.os.linux.mint

On 2025-12-27, Axel <none@not.here> wrote:

Paul wrote:

On Tue, 12/23/2025 11:30 PM, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR technology for normal desktop use

https://www.seagate.com/ca/en/products/cmr-smr-list/

# Makes it pretty clear which ones to avoid

The situation here, is more sketchy.

https://www.reddit.com/r/DataHoarder/comments/1jjt6g3/western_digital_cmrsmr_lists_reliable/

WD Red, Blue, Purple, Gold and WD_BLACK Drives

WD Gold 3.5" - all CMR <=== good, but pricey (may state Helium or Air)

WD_BLACK 3.5" - all CMR <=== some of these are good, try an 8TB one (air breather)
They may not be making 6TB any more. Same platter count, 8TB capacity.
The Helium cannot run out of this one, as this one is air.

WD Blue 3.5" - ignore - depends on size... [download datasheet and check]
CMR WD60EZAX WD40EZAX WD30EZAX
SMR WD60EZAZ WD40EZAZ WD30EZAZ (peaks into Best Buy lock room...)
Larger are CMR, all are air breathers (even 12TB one)

WD Purple Pro 3.5" - all CMR \
\___ Surveillance cam, multi-thread write
WD Purple 3.5" - All CMR /

WD Red Plus 3.5" - All CMR <=== No idea what the intended purpose of these is
Maybe they are whatever the "WD Red" was supposed to be.

WD Red 3.5" - All SMR <=== Name ruined by bad publicity and dishonesty

WD Red Pro 3.5" - All CMR <=== Presumably for NAS

*******

WD Black 2.5" - ignore - depends on size

WD Blue 2.5" - All SMR

WD Red 2.5" (CMR) - no link, but looks like they are all CMR

*******

The HAMR ones are all CMR at the moment, presumably because a
zero clearance shingle would not mix with waving a laser around in there.
The laser might heat up an adjacent track and make the edge of the
track easier to write with a weak field.

*******

Summary: "Cheap" drives in CMR might be harder to find (company stocks the Z ones instead)
You have to be careful in the lowest tier (Barracuda or WD Blue Z)

The drives being flogged by Tomshardware, might not have passed >> some certification which is why they sell at half price. We don't >> know the back-story of such drives, where they came from, how it >> was necessary to "dump them in external enclosures for a song". >> The pricing going on, is not all Sparkle Ponies.

You might find used Chia Pets on Ebay, that have been refurbed and
reset by the unscrupulous. You cannot go to bazaar sites and always
get a good deal. You cannot "squeeze the produce" and spot the
rotten ones.

It's quite the business model, the "anonymous bag of bits" model.

Out of all the drives I've bought, I only ever had one "infant mortality". >> I bought a WD Black 1TB two years ago, the motor was dead. Since drives
are 100% tested, how did that drive "fall off the production line" ?
The tech in the builder-section at the computer store, was also
surprised when he tested it on his rig and he refunded me. It's OK
for a drive to wear out prematurely due to bad design, it's quite
another for one to not work at T=0. But it happens I guess.

thanks for this. I've been checking on drives too myself. problem is not
all makes/models are stocked by computer shops, and I don't want to
spend a lot. I have been re-purposing what I have here to free up a 1Tb drive, but if I need to buy a new drive, do you think SMR would be Ok
for desktop use, and/or data storage, or should I only buy CMR?

I have the feeling that SMR got a bad reputation when it came out. It was considered a hack and somewhat inferior to CMR. The question is what do you want to use it for? As SMR has to shuffle the data around to get the data
onto the disk or when it needs to read the layer on the bottom. This slows things down. Then again a CMR disk is so slow compared to a SSD.

To be clear SMR can not keep up with CMR for NAS use. However in my
experience the slower speed it no noticable in a practiable way.

Getting the OS onto a SSD does make a noticable difference. Worth the effort and the cost. A small(ish) SSD for the /root, and /home partition. You can then create a Data partition on a HDD.


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From Newsgroup: alt.os.linux.mint

On Sat, 12/27/2025 4:05 PM, Gordon wrote:

On 2025-12-27, Axel <none@not.here> wrote:

Paul wrote:

On Tue, 12/23/2025 11:30 PM, Axel wrote:

It's become very difficult nowadays to buy new hard drives using CMR technology for normal desktop use

https://www.seagate.com/ca/en/products/cmr-smr-list/

# Makes it pretty clear which ones to avoid

The situation here, is more sketchy.

https://www.reddit.com/r/DataHoarder/comments/1jjt6g3/western_digital_cmrsmr_lists_reliable/

WD Red, Blue, Purple, Gold and WD_BLACK Drives

WD Gold 3.5" - all CMR <=== good, but pricey (may state Helium or Air)

WD_BLACK 3.5" - all CMR <=== some of these are good, try an 8TB one (air breather)
They may not be making 6TB any more. Same platter count, 8TB capacity.
The Helium cannot run out of this one, as this one is air.

WD Blue 3.5" - ignore - depends on size... [download datasheet and check]
CMR WD60EZAX WD40EZAX WD30EZAX
SMR WD60EZAZ WD40EZAZ WD30EZAZ (peaks into Best Buy lock room...)
Larger are CMR, all are air breathers (even 12TB one)

WD Purple Pro 3.5" - all CMR \
\___ Surveillance cam, multi-thread write
WD Purple 3.5" - All CMR /

WD Red Plus 3.5" - All CMR <=== No idea what the intended purpose of these is
Maybe they are whatever the "WD Red" was supposed to be.

WD Red 3.5" - All SMR <=== Name ruined by bad publicity and dishonesty

WD Red Pro 3.5" - All CMR <=== Presumably for NAS

*******

WD Black 2.5" - ignore - depends on size

WD Blue 2.5" - All SMR

WD Red 2.5" (CMR) - no link, but looks like they are all CMR

*******

The HAMR ones are all CMR at the moment, presumably because a
zero clearance shingle would not mix with waving a laser around in there. >>> The laser might heat up an adjacent track and make the edge of the
track easier to write with a weak field.

*******

Summary: "Cheap" drives in CMR might be harder to find (company stocks the Z ones instead)
You have to be careful in the lowest tier (Barracuda or WD Blue Z)

The drives being flogged by Tomshardware, might not have passed >>> some certification which is why they sell at half price. We don't
know the back-story of such drives, where they came from, how it >>> was necessary to "dump them in external enclosures for a song". >>> The pricing going on, is not all Sparkle Ponies.

You might find used Chia Pets on Ebay, that have been refurbed and
reset by the unscrupulous. You cannot go to bazaar sites and always
get a good deal. You cannot "squeeze the produce" and spot the
rotten ones.

It's quite the business model, the "anonymous bag of bits" model.

Out of all the drives I've bought, I only ever had one "infant mortality". >>> I bought a WD Black 1TB two years ago, the motor was dead. Since drives
are 100% tested, how did that drive "fall off the production line" ?
The tech in the builder-section at the computer store, was also
surprised when he tested it on his rig and he refunded me. It's OK
for a drive to wear out prematurely due to bad design, it's quite
another for one to not work at T=0. But it happens I guess.

thanks for this. I've been checking on drives too myself. problem is not
all makes/models are stocked by computer shops, and I don't want to
spend a lot. I have been re-purposing what I have here to free up a 1Tb
drive, but if I need to buy a new drive, do you think SMR would be Ok
for desktop use, and/or data storage, or should I only buy CMR?

I have the feeling that SMR got a bad reputation when it came out. It was considered a hack and somewhat inferior to CMR. The question is what do you want to use it for? As SMR has to shuffle the data around to get the data onto the disk or when it needs to read the layer on the bottom. This slows things down. Then again a CMR disk is so slow compared to a SSD.

To be clear SMR can not keep up with CMR for NAS use. However in my experience the slower speed it no noticable in a practiable way.

Getting the OS onto a SSD does make a noticable difference. Worth the effort and the cost. A small(ish) SSD for the /root, and /home partition. You can then create a Data partition on a HDD.

But the times modulate the logic, and there really isn't a good strategy
any more. I agree with your strategy, but the cupboards are "mostly bare"
or "contain inferior items".

The best I can do here, is a Samsung 870 EVO 512GB (for a SATA), and the flash is unlikely
to get mushy on that. I have a handful of Lexar NS100, which are half the price of a Samsung, but they get mushy after three months, and the firmware does not seem to be freshening them (which would trade wear life for perky performance).

You could put "everything you own" on a WD Black 2TB. But that's still relatively expensive. The cheapest I could get a WD Black 1TB when they
were making them, was about $65 CDN. And the situation now, isn't all that clear.
The catalog seems to list WD Black 500GB, and when they were making those,
one of the ones I bought was short stroked, which means the heads only
cover 50% of the platter surface on a 1TB platter (which is nice). This
implied they didn't have the platters any more, to make 500GB drives,
and yet the 500GB drive is listed (I can't get it), and the WD Black 1TB
is no longer made (as most platters now are 2TB and they'd have to short
stroke one of those to make a 1TB from a 2TB platter).

The low end is "slim pickings". I would not recommend a WD Blue, and even if you did go that way, you probably can't buy a "small" one of those. The WD Black
is a better overall drive. Best Buy only stocks WD Blue, which tells you
where the profit margin is. I find it hilarious they keep the drives in
a "lock room", when no thief is going to steal a WD Blue :-) My regular computer
store keeps them behind the counter, but they don't lock them in the "cage"
at night.

I have two WD Blue. One came in a refurb computer, and it got retired
for being naughty. But the older one, a 4GB hard drive, that still works,
ball bearings and all. It's not very fast... I've got a ZIP 250 drive,
that I bet it is as fast as the old WD Blue.

Really, you have to look at your store stock, to make a plan. My store
has been running on "zero stock" for a couple of years, and that pre-dates
the lunacy situation at retail right now. The news yesterday, is video cards are now supposed to be in short supply. The RTX 5090 have been pretty thin
for months, so it wouldn't exactly be a surprise to see those disappear.
And when I bought my "cheesy" GT1030 a couple weeks ago, I know that the
only reason they exist, is they were new old stock sitting somewhere,
and those were not specially made three weeks ago for fun.

It's a hell of a time to have computers for a hobby.

Paul


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From Newsgroup: alt.os.linux.mint

On 25/12/2025 4:57 am, Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 21:18:19 +1000, keithr0 wrote:

On 24/12/2025 3:33 pm, Lawrence DrCOOliveiro wrote:

I got a new 12TB drive for my backup machine just a couple months
ago.

That's a lot of eggs in one basket ...

ThatrCOs why I have a backup machine.

... personally I'd prefer a RAID 5 or 6 setup with smaller drives.

RAID is about high availability, not about backup.

RAID is about failure resilience, if you have a single drive a failure
loses everything. Make a RAID group, and the loss of a single drive
results in no data loss. Done properly, it also improves performance.
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: alt.os.linux.mint

On Sun, 28 Dec 2025 09:50:50 +1000, keithr0 wrote:

On 25/12/2025 4:57 am, Lawrence DrCOOliveiro wrote:

RAID is about high availability, not about backup.

RAID is about failure resilience, if you have a single drive a
failure loses everything.

With JBOD, you only lose what was on that drive.

With RAID-0, you do indeed lose everything.

The point with (nonzero) RAID is to keep going while you restore from
backup. ItrCOs not about replacing the need for backup.
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From Newsgroup: alt.os.linux.mint

On 28/12/2025 10:07 am, Lawrence DrCOOliveiro wrote:

On Sun, 28 Dec 2025 09:50:50 +1000, keithr0 wrote:

On 25/12/2025 4:57 am, Lawrence DrCOOliveiro wrote:

RAID is about high availability, not about backup.

RAID is about failure resilience, if you have a single drive a
failure loses everything.

With JBOD, you only lose what was on that drive.

With RAID-0, you do indeed lose everything.

The point with (nonzero) RAID is to keep going while you restore from
backup. ItrCOs not about replacing the need for backup.

Not exactly, with any useful sort of RAID implementation, you can hot
replace the bad drive, without the need to restore from backup. All the
data remains available throughout.

I spent 20 years working on large storage systems, beginning with boxes
of 128 5 1/4" 9gig SCSI drives, going on with larger and larger drives dropping to 3 1/2" SCSI then Ultra SCSI, fibre channel and finally SOS
(SCSI Over Serial) drives. The largest box that I encountered had 1700
400gig drives. Originally all drives were RAID 1, then RAID 5, and later
to RAID 6. The customers were mostly large mainframe sites, both IBM,
and *nix who had to have their data available 24/365 no ifs no buts.
After all, you aren't going to be well pleased if you can't get your
money from an ATM because the bank is having to restore it's database
from a backup due to a drive failure.

Backups were made, usually on large ATA drives, but more for recovery
from software or system errors rather than hardware failures


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From Newsgroup: alt.os.linux.mint

On Sun, 28 Dec 2025 11:12:22 +1000, keithr0 wrote:

... with any useful sort of RAID implementation, you can hot replace
the bad drive, without the need to restore from backup.

ThatrCOs where the rCLhigh availabilityrCY comes in.

All the data remains available throughout.

Until you discover a software bug (or an operator screwup) has deleted
an important database. Which you then need to restore from ... where?

I spent 20 years working on large storage systems, beginning with
boxes of 128 5 1/4" 9gig SCSI drives, going on with larger and
larger drives dropping to 3 1/2" SCSI then Ultra SCSI, fibre channel
and finally SOS (SCSI Over Serial) drives.

Presumably, judging from your comments, you were more on the hardware
side, not the software side.
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On 28/12/2025 12:43 pm, Lawrence DrCOOliveiro wrote:

On Sun, 28 Dec 2025 11:12:22 +1000, keithr0 wrote:

... with any useful sort of RAID implementation, you can hot replace
the bad drive, without the need to restore from backup.

ThatrCOs where the rCLhigh availabilityrCY comes in.

All the data remains available throughout.

Until you discover a software bug (or an operator screwup) has deleted
an important database. Which you then need to restore from ... where?

Of course there were still backups, not always what you think though.
The machines that I worked on could take checkpoints online, some users checkpointed on an hourly basis.

Resilience was an important facto with our customers, another storage
server could be connected vie optical fibre, the slave machine being a
remote mirror of the the master. After the Twin Towers incident, some customers took it even further. Maybe the master was in New York, the
first slave 50Km away in New Jersey, and a second slave connected to the
first across the continent in LA or San Francisco. The first slave would
be one transaction max behind, the second several, as a last ditch copy.
The slaves could also be used as a test load for system changes and
resynced afterward.

I spent 20 years working on large storage systems, beginning with
boxes of 128 5 1/4" 9gig SCSI drives, going on with larger and
larger drives dropping to 3 1/2" SCSI then Ultra SCSI, fibre the first channel
and finally SOS (SCSI Over Serial) drives.

Presumably, judging from your comments, you were more on the hardware
side, not the software side.

I worked on the hardware side for 30 years then wrote software
professionally for another 25. I still write stuff for micro controllers
like the ESP32 and the Raspi Pico for fun.
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On Sat, 12/27/2025 6:50 PM, keithr0 wrote:

On 25/12/2025 4:57 am, Lawrence DrCOOliveiro wrote:

On Wed, 24 Dec 2025 21:18:19 +1000, keithr0 wrote:

On 24/12/2025 3:33 pm, Lawrence DrCOOliveiro wrote:

I got a new 12TB drive for my backup machine just a couple months
ago.

That's a lot of eggs in one basket ...

ThatrCOs why I have a backup machine.

... personally I'd prefer a RAID 5 or 6 setup with smaller drives.

RAID is about high availability, not about backup.

RAID is about failure resilience, if you have a single drive a failure loses everything. Make a RAID group, and the loss of a single drive results in no data loss. Done properly, it also improves performance.

RAID is about delaying maintenance until after the work day is done.

It's nothing about long term resilience.

If you have one fault and you do not meet the MTTR, the second
fault might knock you out, or depending on RAID class, the third
fault might knock you out.

*******

You really really have not thought it through, if you believe that resilience thing.

At 2PM in the afternoon at work, the main CAD server (serves copies of CAD software), I can't remember if it was a PERC or what it was.

The *controller* wrote to all drives at once. It was
not a commanded write. It was a firmware issue of some sort.
And not a capacity-rollover type flaw.

It corrupted some area low in the disk storage.

Causing *all volumes to be wiped out instantly*.

The restore time for the server, ran past 5PM and the
five hundred engineers depending on the server for their
software, had long since gone home when the server came back up.
Somebody in management, did the calc to see what the
"lost time" had cost us. That's what was the first step in
figuring out what the response should be to the event.

And this failure happened *twice*, just on a different server
which was not as critical. Because the first incident was not
as critical, it wasn't taken as seriously and nobody at that
time, had figured what had happened to the server. It was only
when a major infrastructure incident was raised, that the event
was analyzed to its source.

This is why RAID is worth *nothing* to you.

There is a class of "common mode faults" you should consider.

An example of a common mode fault, is when the PSU +12V shoots
up to +15V and burns all disk drives. When I mentioned the possibility
of this happening, a poster wrote in and said this had happened
to him. Loss of all storage on a PSU fault.

This is *why we do backups of our RAID array* :-/

A RAID array is NOT a backup.

A mirror, is just so much bullshit for the people doing it.
Because they haven't thought about the common mode faults.

I can give an example from a USENET posting about a RAID1 two disk mirror.

A user is running RAID 1. One of the drives drops. The user thinks
this is fine and dandy. Plug in replacement drive, and oh... whats this ?
The files on the second drive, stopped updating three months ago.
The array had some kind of fault, where the controller was
not writing to the second (surviving) drive. Which means, sure,
you can do a RAID rebuilt of your mirror, but three months
worth of changes are missing. The controller in this case was
a SIL3112, so it wasn't an actual quality controller. It's just
the deception "you have RAID", that counts.

DO YOUR BACKUPS. And run a Verify on your backup, to ensure it is a good one.
I have stories about that, too :-)

Paul
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On Sun, 28 Dec 2025 04:41:43 -0500, Paul wrote:

The *controller* wrote to all drives at once. It was not a commanded
write. It was a firmware issue of some sort. And not a
capacity-rollover type flaw.

It corrupted some area low in the disk storage.

Causing *all volumes to be wiped out instantly*.

Let me just add that to my ever-lengthening list of reasons why I
dislike hardware RAID controllers.

If IrCOm going to use RAID, I recommend using the built-in Linux
software RAID. I have seen it deal with failures more than once, and
my respect for it has only gone up.

Not to mention, itrCOs so much easier to reconfigure without having to
mess around with obscure vendor-proprietary utilities.

This is *why we do backups of our RAID array* :-/

A RAID array is NOT a backup.

Agree, agree, thrice agree.
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