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

[Lightner, Jeff]

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.





-----Original Message-----
From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of Ron Frazier
Sent: Thursday, October 27, 2011 8:53 PM
To: Atlanta Linux Enthusiasts
Subject: Re: [ale] semi OT - to SSD or not to SSD

I found some further information I thought I'd share by Googling SSD
reliability.

This article investigates the issue:

http://www.tomshardware.com/reviews/ssd-reliability-failure-rate,2923.html

And on page 7, at this link:

http://www.tomshardware.com/reviews/ssd-reliability-failure-rate,2923-7.html

we find this quote:

<quote on>

Despite SLC-based drives accounting for only a fraction of the NAND
market, we have much more data on SLC-based SSDs than we do on those
using MLC technology. Even though our data set is one-twentieth the size
of previous studies on hard drives, our information starts to suggest
that SLC-based SSDs are no more reliable than SAS and SATA hard drives.

If you are a consumer, this has major implications. SSD makers have been
trying to emphasize that they're offering two major benefits: better
performance and better reliability. However, if the data on a SSD is no
safer than it is on a hard drive, then performance is the real reason
you'd want to explore solid-state storage.

<quote off>

I thought that was interesting. The article points out that SSD's may
tend to fail irrecoverably more than HDD's, from which data can often be
recovered after a failure.

Sincerely,

Ron


On 10/27/2011 7:46 PM, Ron Frazier wrote:
> Hi all,
>
> In another recent thread, the subject of SSD and flash memory
> reliability came up, although that wasn't the title of the subject.  I
> want to explore that a bit.  In the other thread, I said I have
> personally seen failures in memory sticks, memory cards, a GPS that
> suddenly refused to work and refused initially to take a firmware
> update, and routers that occasionally flake out and need to have their
> firmware refreshed.

<snip>


--

(PS - If you email me and don't get a quick response, you might want to
call on the phone.  I get about 300 emails per day from alternate energy
mailing lists and such.  I don't always see new messages very quickly.)

Ron Frazier

770-205-9422 (O)   Leave a message.
linuxdude AT c3energy.com

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