[ale] semi OT - to SSD or not to SSD

Richard Bronosky Richard at Bronosky.com
Sat Oct 29 16:48:31 EDT 2011


1. A device with no moving parts  is safer than on a drive that spins at
5400 or 7200 RPMs. SSDs are not subject to mechanical failures and much more
tolerant of percussion shock. This makes them especially well suited for
mobile applications.

2. In any computer an SSD is going to out perform an HDD.

3. An SSD has wear leveling an produces less heat than an HDD. They are
presumed to be at least as reliable as their predecessor technology. And
their low operating temperatures make them less likely contribute or succumb
to "peer failure" (lots of drives producing lots of heat).

4. Backup drives should only be in use while backing up or recovering data.
They should never fail because they should only see a few hundred hours of
operation. For this reason the biggest concern is GB/$. Today the best bet
is HDD. I stay away from the highest density drives on the market.
On Oct 28, 2011 12:40 PM, "Jeff Hubbs" <jhubbslist at att.net> wrote:

> On 10/28/11 9:06 AM, Lightner, Jeff wrote:
> > We use SSDs in a high end disk array for our main Production DB (we got
> the array just about a year ago).  Performance has been exceptional and so
> far the only drive that has failed in the array was one of the SATA drives
> not one of the SSDs.
> >
> > On the flip side we tried to use one of the FusionIO SSD cards and
> experienced significant data loss due when it failed.   The card has
> redundancy on the RAM and an algorithm to help prevent overuse of any given
> bit.   The flaw in using a single one was that the ROM chip itself failed
> thereby preventing access to the RAM and the algorithm.   The lesson from
> this for me is that one should NOT use a single SSD any more than they
> should rely on a single IDE, SAS or SATA.   Had we mirrored the cards we'd
> not have lost the data.  Of course that is cost prohibitive.   Additionally
> the cards are very sensitive to heat.
> >
> > So far haven't used SSDs as boot drives but so long as they were in a
> RAID configuration I'd have no more qualms about using them than IDE, SAS or
> SATA and given performance increase would definitely prefer SSDs.
> I did this on a 4.5TB (effective) file server I built for my previous
> employer using Supermicro hardware (saved them tens of thousands over an
> IBM-rebadged NetApp SAN appliance that was junk).  Two Imation SSD
> drives inside the cabinet, small boot partitions on each and then a
> partition on each RAID1ed via md for /.  /var was on a pair of 80GB
> SATAs on the front.  The SSDs did survive a ~120F baking for a few
> hours; two of the eight 1TB SATAs (four RAID10s) went out of spec but no
> data was lost.
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