[ale] no putting swap on ssd

Greg Freemyer greg.freemyer at gmail.com
Mon Feb 7 18:51:25 EST 2011


On Mon, Feb 7, 2011 at 5:20 PM, Greg Freemyer <greg.freemyer at gmail.com> wrote:
> On Mon, Feb 7, 2011 at 4:52 PM, Sparr <sparr0 at gmail.com> wrote:
>> This is mostly bogus out-of-date information. Yes, SSDs (and other
>> solid state storage like SD cards) have a limited lifetime, but it far
>> exceeds their useful lifetime these days.
>>
>> Assume we have wear leveling, so that single sectors don't go bad prematurely.
>>
>> At 50 megabytes per second of continuous writing (which is insane for
>> any storage device except always-on video recording), a 16GB storage
>> device with a lifetime of 1 million writes means it's going to fail in
>> TEN YEARS.
>
> I guess I'm way behind the times thinking its 10,000 writes per EB.  I
> just pulled up the Intel® X25-V SSD spec. to see what it is, but it
> doesn't have the number of writes provided in the spec. :(
>
> I'll assume your 1,000,000 number is right even in the "value" SSDs.
>

Okay, I continued googling and found this:

http://www.xbitlabs.com/news/storage/display/20100615213913_Intel_to_Use_Enterprise_MLC_in_Next_Gen_Enterprise_Solid_State_Drives.html

It says the MLC flash chips were getting 5,000 write cycles, but
Micron introduced the eMLC Nand chips that are spec'ed for 30,000
write cycles.

Elsewhere I found that the Intel Value line SSDs are based on MLC
chips.  So I would take that 1,000,000 number with a large grain of
salt.  In fact, my 10,000 number may too large.  Hard to tell since
Intel is apparently not making the number easily available and it
could be anywhere in the 5,000 to 30,000 range.

If 10,000 is right and you follow my original logic, the 400 days of
continuous operation drops to 4 days of continuous operation!

That's impressive!  But not in a positive way.

Greg



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