Leslie Rhorer wrote:
-----Original Message-----
From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-
owner@xxxxxxxxxxxxxxx] On Behalf Of David Rees
Sent: Monday, November 01, 2010 4:26 PM
To: John Robinson
Cc: Mark Knecht; Linux-RAID
Subject: Re: Samsung F1 RAID Class SATA/300 1TB drives
On Thu, Oct 28, 2010 at 4:37 PM, John Robinson
<john.robinson@xxxxxxxxxxxxxxxx> wrote:
On 29/10/2010 00:17, Mark Knecht wrote:
I saw in Fry's San Jose ad today they were selling these
Serial-ATA/300 drives for $67. They didn't give a model number but
scouting around a bit on the web I'm guessing they are a discontinued
model.
Any inputs on whether these are drives that work well with mdadm RAID?
Do they support TLER and otherwise work well?
This would just be a home server of some type, nothing industrial.
Probably a 3 drive RAID-1 or something like that.
Well, they're perhaps not great. I bought three and after only about a
thousand hours one of them was giving SMART errors, then after about
7,500
hours a second one started doing it too. At that point I replaced both
with
other makes, copying over with ddrescue (or maybe it was dd_rescue),
which
worked without any failed sectors, then ran badblocks -w on the Samsungs
and
the SMART errors went away. The third one of mine is still fine, and the
other two are now in a ReadyNAS giving good service.
I think that using two different brand drives in general is a good idea.
We recently had 2 500 GB WD5000AAKS drives die at the same time over a
weekend. Both of them suffered from the same death and would no
longer spin up - just making a clicking/whirring sound when you
powered it on.
Luckily we had backups for most of the data on there, but some
non-critical (but time consuming to manually restore) data had to be
reconstructed.
I understand that drives from the same batch will often die around the
same period of time - from now on we plan on trying to use dissimilar
drives when possible.
First time we've seen 2 drives in one array die that close together
and that catastrophically, though.
I had 4 Seagate drives go bad all at once on a 10 drive array.
Fortunately, the drives did not die entirely. Indeed, I'm still not sure
what is wrong with them. They seem to read and write just fine, but if they
are added back to the array and the array is asked to access data with a
high seek rate (read or write), the drives get kicked from the array.
Relatively low seek rates allow the drives to continue to be array members,
and when the drives get kicked, they can always be added back. I was able
to use ddrescue to read the data 100% without any failures. Had the array
been unrecoverable, I had backups, of course, but I did not have to resort
to them. I'm not entirely sure when the drives all went bad, but it was
within a week or two of each other.
One possible cause for this is a marginal power supply which "can't keep
up" when supporting lots of seeks and transfers on multiple drives. In
every group of drives there will be some variance for low voltage (or
noise, more likely) and the drive(s) which are sensitive appear to fail.
I say this from experience, it does happen, and going to a better power
supply will cure it. This might not be the problem, of course, but it's
worth investigating before blaming the drives.
The sad truth is that if you have this problem and replace the weakest
drives, it's likely that some other drive will become the weak sister
and fail, leading to people saying "oh, those {vendor} drives are crap,
I had {number} fail on me, one after the other." Have you heard that?
Me, too! Check before replacing or scrapping drives!
--
Bill Davidsen<davidsen@xxxxxxx>
"We can't solve today's problems by using the same thinking we
used in creating them." - Einstein
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