Preserving SSDs

Folderol

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Nov 12, 2012, 6:12:41 PM11/12/12

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I'll be getting a new machine (hopefully) tomorrow with a 180G SSD, and will be
putting debian wheezy on it. I'd like to minimise unnecessary writes so would
appreciate some suggestions.

Something I know how to do:
edit fstab to include noatime

Things I have some idea about but don't know how to do:
don't have a swap partition - the debian installer doesn't seem to want
to let me do that :(
point /tmp to a ramdisk

Things for when everything is completely tickety-boo:
point var/log to /dev/null
disable xsession errors, bash history (any others)

Any thoughts on these points, or other things I should consider?

What FS would people suggest for the '/' and 'home' partitions?

--
Will J G

Richard Kettlewell

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Nov 12, 2012, 6:31:55 PM11/12/12

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Folderol <fold...@ukfsn.org> writes:
> I'll be getting a new machine (hopefully) tomorrow with a 180G SSD,
> and will be putting debian wheezy on it. I'd like to minimise
> unnecessary writes so would appreciate some suggestions.
>
> Something I know how to do:
> edit fstab to include noatime
>
> Things I have some idea about but don't know how to do:
> don't have a swap partition - the debian installer doesn't seem to want
> to let me do that :(
> point /tmp to a ramdisk

In /etc/fstab:

tmpfs /tmp tmpfs defaults,size=1G,nr_inodes=256k,nosuid 0 0

Vary the size and nr_inodes parameters to taste.

> Things for when everything is completely tickety-boo:
> point var/log to /dev/null
> disable xsession errors, bash history (any others)
>
> Any thoughts on these points, or other things I should consider?

I think you are being overly paranoid about flash wear.

--
http://www.greenend.org.uk/rjk/

Message has been deleted

Geoff Clements

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Nov 13, 2012, 8:46:42 AM11/13/12

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For your "normal" partions use ext4 with the "discard" option.

--
Geoff

Greg Hennessy

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Nov 14, 2012, 6:29:48 AM11/14/12

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On Mon, 12 Nov 2012 23:12:41 +0000, Folderol <fold...@ukfsn.org> wrote:

>I'll be getting a new machine (hopefully) tomorrow with a 180G SSD, and will be
>putting debian wheezy on it. I'd like to minimise unnecessary writes so would
>appreciate some suggestions.
>

Seriously, don't waste your time.

Any [rd]ecent SSD can handle a full disk worth of writes every day for 4-5
years, the wear levelling algorithms ensure that all cells take their fair
share. Just make sure Trim is enabled.

greg

--
?¡aah, los gringos otra vez!?

Gordon

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Nov 15, 2012, 2:59:03 AM11/15/12

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This idea is gaining ground from what I have read.

Lets go back to the days of the 20*MB* HD. These tended to fail rather more
often than to-days 2 TB models. Time has caused great improvements.

The first SSD's tended to blow up shortly after launch. Time has worked on
this problem.

Here is a thought. Even without use it is estimated that a SSD will die in
ten years.

They arer getting cheaper, so by the time the current one dies, you will be
able to by more capacity for the same price and you do always back up your
data, so what is ones concern?

Richard Kettlewell

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Nov 15, 2012, 3:47:02 AM11/15/12

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Gordon <Gor...@clear.net.nz> writes:
> Here is a thought. Even without use it is estimated that a SSD will die in
> ten years.

Estimated by who?

--
http://www.greenend.org.uk/rjk/

unruh

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Nov 15, 2012, 12:13:15 PM11/15/12

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On 2012-11-15, Richard Kettlewell <r...@greenend.org.uk> wrote:
> Gordon <Gor...@clear.net.nz> writes:
>> Here is a thought. Even without use it is estimated that a SSD will die in
>> ten years.
>
> Estimated by who?

For example
http://www.storagesearch.com/ssdmyths-endurance.html

which argues that under the worst possible scenario (a constant 80MB/s steaming
write to the ssd)
"The end result is 51 years!"

(The first entry in google to "ssd lifetime")

Conclusion:
"With current technologies write endurance is not a factor you should be
worrying about when deploying flash SSDs for server acceleration
applications - even in a university or other analytics intensive
environment. "
>

Folderol

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Nov 15, 2012, 5:43:15 PM11/15/12

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Int'restin'

I think I will still at least do the noatime and discard thing though. A for
the rest, it depends on how much I end up worrying :)

I've now got the beast and am very pleased with it. I've installed
debian-squeeze without any problems at all. It is being used as a DAW so I've
also installed a lot of synth stuff.

Sequencer + synth recording of complex material that used to peak at around
70% total processor, now peaks at around 20%!

Spec:
AMD A8-5600K Quad Core APU (3.6GHz) & Radeon™ HD 7560D Graphics
ASUS® F2A55-M LE
4GB SAMSUNG DUAL-DDR3 1333MHz
120GB INTEL® 330 SERIES SSD, SATA 6 Gb/s '/' & /home'
180GB INTEL® 330 SERIES SSD, SATA 6 Gb/s '/audio' & '/source'

--
W J G

Greg Hennessy

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Nov 16, 2012, 6:44:02 PM11/16/12

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On Thu, 15 Nov 2012 22:43:15 +0000, Folderol <fold...@ukfsn.org> wrote:

[snip]

>>
>> Conclusion:
>> "With current technologies write endurance is not a factor you should be
>> worrying about when deploying flash SSDs for server acceleration
>> applications - even in a university or other analytics intensive
>> environment. "
>> >
>
>Int'restin'
>
>I think I will still at least do the noatime and discard thing though. A for
>the rest, it depends on how much I end up worrying :)
>

Take a look at the MLC versus TLC wear figures over time in the table here

http://www.anandtech.com/show/6459/samsung-ssd-840-testing-the-endurance-of-tlc-nand

and if you really need convincing, someone has stepped up and performed a
heroic series of endurance tests here

http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm

It really is a non issue.

unruh

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Nov 18, 2012, 12:48:11 PM11/18/12

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On 2012-11-12, Folderol <fold...@ukfsn.org> wrote:
> I'll be getting a new machine (hopefully) tomorrow with a 180G SSD, and will be
> putting debian wheezy on it. I'd like to minimise unnecessary writes so would
> appreciate some suggestions.
>
> Something I know how to do:
> edit fstab to include noatime
>
> Things I have some idea about but don't know how to do:
> don't have a swap partition - the debian installer doesn't seem to want
> to let me do that :(
> point /tmp to a ramdisk
>
> Things for when everything is completely tickety-boo:
> point var/log to /dev/null
> disable xsession errors, bash history (any others)
>
> Any thoughts on these points, or other things I should consider?

Yes, you should consider that modern ssd drives are designed to make
sure that those attempts are pointless. Lifetimes of ssd drives are now
long enought that you will have to worry about your own reboot before
the drives fail

chris

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Nov 19, 2012, 4:32:47 AM11/19/12

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Especially as you should be relying on a good backup strategy rather
than trying to avoid failure.