Re: [gentoo-user] {OT} Anyone tried a solid state drive?

[Joshua Murphy]

On Thu, Nov 27, 2008 at 5:26 AM, Stroller
<stroller@××××××××××××××××××.uk> wrote:
>
> On 27 Nov 2008, at 02:08, Volker Armin Hemmann wrote:
>>
>> On Donnerstag 27 November 2008, Grant wrote:
>>>
>>> I'm considering buying a solid-state drive to improve I/O performance
>>> and even reduce noise.  Has anyone tried this?  I was considering
>>> getting the lowest capacity I can find and putting most of the system
>>> on it.  There is a roundup on tomshardware.com and it sounds like some
>>> are very much better than others.  SLC sounds vastly superior compared
>>> to MLC, but also much more expensive.
>>>
>>
>> http://valhenson.livejournal.com/25228.html
>>
>> I would rethink that after reading that post.
>
> From TFA:
>
>   Postscript: Yes, this analysis is based on anecdotal evidence and
>   personal experience, but I can't afford the time to do real research
>   unless someone pays me to. If you know someone who will, send me
>   email!
>
> I've read a number of other reports, also based on anecdotal evidence and
> personal experience, from a number of people who have very happily been
> using flash as root volumes for years. Their opinions disagree with TFA.
>
> Typically the reports I've read have been from people using CFcards - 4gig
> is now unbelievably cheap, and CFcards talk EIDE with only a small, cheap
> physical adaptor - on MythTV frontends & low-overhead servers. CFcards look
> ideal for these purposes because they're quiet - you want to minimise noise
> when playing back video in the living room, for instance.
>
> I think the last anecdote I read on this subject was written by Trubox
> (Truebox?) on the Openmoko-community list a month or two ago. They sell
> Aserisk systems to small business (in my area, as it happens) and I would
> imagine that typically the system sits in the corner of an office and is
> untouched for years at a time. I would imagine that have plenty of installed
> systems throughout the UK (otherwise they'd be going hungry). They report a
> very low failure rate, as did someone else on the MythTV-users list who also
> bases a commercial offering on flash-based hardware.
>
> Whilst I would probably, myself, install a second flash drive myself &
> back-up (to a stage 4?) periodically, and avoid disk-writes when logging, I
> get the strong impression that there's little to be scared of using flash
> memory.
>
> Everything I read that says flash - and particularly its wear-levelling - is
> unsuitable for this purpose makes sense to me, but it doesn't jibe with the
> real-world experiences of those who ARE using flash VERY happily.
>
> I've yet to see empirical evidence on the longevity of flash for this
> purpose, but I'd advise anyone considering it - anyone thinking flash
> unsuitable - to search the mailing lists I've mentioned. The Trubox post
> should be easy to find, and the subject comes up on MythTV-users every few
> months.
>
> Stroller.

The catch, though, is that I'd guess commercial offerings of MythTV
boxes like that would be updated infrequently and that the actual
recording storage, and likely logs and other frequent write files, is
done on a normal disk. It doesn't seem logical for the average Gentoo
user that follows the 'update often' mentality, and someone looking to
milk the very top in the way of speed out of their system through disk
throughput is very likely a 'ricer' in other respects. When you start
using it for frequent writes (like your average system with everyday
use and frequent upgrades) you start getting a little closer to the
line on write cycles for small-sized MLC... but SLC is going to, by my
guess, outlast its speed benefits by far (much like the old 800MB
harddrives I have around that have far outlasted their size benefits
from their day). Looking at SLC from a $$/GB standpoint you'll find
they're horrendous, but from a $$/performance... at the very least
Intel's X25-E starts to look a lot more reasonable for its cost (it's
easily enterprise grade and mops the floor with just about anything
else that holds data through a reboot)... which is around $760 for the
32MB model.

On the topic of using CF for the job... just looking at
http://www.robgalbraith.com/bins/multi_page.asp?cid=6007, which
doesn't take CF -> SATA adaptors into account, the highest read speed
across the board is about 50MB/s, which is half of what the
Velociraptor averages (and 1/5 of its burst read).

-- 
Poison [BLX]
Joshua M. Murphy