topic Re: Intel SSD Media Wearout in Archive

Intel SSD Media Wearout

idata — Wed, 29 Jun 2011 09:19:53 GMT

Dear users,

I would like to know what the lowest media wear out level anyone has experienced using his / her Intel SSD (please also state the lifetime of your drive; this will give me a good indication). Furthermore I would like to use the drive for some research which involves large data sets (usage of max. 10TB a day). Would it be advisable to buy a SSD?

In this video (/community/tech/solidstate http://communities.intel.com/community/tech/solidstate), someone from Intel stated: "That if the number is approaching zero, you should be really careful". What does approaching zero means in this context? Should like 20 be stated as approaching zero or should it really be like <10?

Thank you for your answers.

Re: Intel SSD Media Wearout

ZStan — Wed, 29 Jun 2011 17:37:15 GMT

here you go..

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

Re: Intel SSD Media Wearout

idata — Thu, 30 Jun 2011 02:02:45 GMT

Hello Blanket,

There are leaked Intel SSD roadmaps on the web that talk about "Lyndonville". According to this website, this may use enterprise-MLC Nand to dramatically increase the Nand flash lifetime. This may be ideal for your usage model:

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

Re: Intel SSD Media Wearout

idata — Sat, 02 Jul 2011 16:07:35 GMT

Does TRIM work correctly on an OS software raid

whose members are set to AHCI mode e.g. for dedicated data partition(s)?

As a general rule, should MLC SSDs be assembled in RAID 0 arrays,

in order to spread the wear?

In other words, is this theoretically correct and can this be confirmed experimentally ...

50% reduction per drive w/ 2 x SSDs in RAID 0? (half as much per drive) 67% reduction per drive w/ 3 x SSDs in RAID 0? (one-third as much per drive) 75% reduction per drive w/ 4 x SSDs in RAID 0? (one-fourth as much per drive)

Lastly, has Intel done any research using SSDs with Windows NTFS compression enabled?

(in drive letter Properties, see: "Compress drive to save disk space" and a check box)

Thanks!

MRFS

Re: Intel SSD Media Wearout

idata — Sun, 03 Jul 2011 01:29:37 GMT

The more data written to a SSD, the more wear occurs regardless of RAID or not. So yes, there is an about 50% reduction in writes on a single member of a 2xRAID0.

As for NTFS Compression: http://blogs.msdn.com/b/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx http://blogs.msdn.com/b/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx

Is NTFS Compression of Files and Directories recommended on SSDs?

Compressing files help save space, but the effort of compressing and decompressing requires extra CPU cycles and therefore power on mobile systems. That said, for infrequently modified directories and files, compression is a fine way to conserve valuable SSD space and can be a good tradeoff if space is truly a premium.

We do not, however, recommend compressing files or directories that will be written to with great frequency. Your Documents directory and files are likely to be fine, but temporary internet directories or mail folder directories aren't such a good idea because they get large number of file writes in bursts.

Re: Intel SSD Media Wearout

idata — Sun, 03 Jul 2011 08:48:26 GMT

Thanks! Based on those graph in the frist post link, I would conclude that it is still not suitable yet for my research data to be stored there. However maybe instead of tackling the problem from the SSD side, I can tackle the problem from writing less.

Thanks all for your answers, you've all been very helpful to me!

Re: Intel SSD Media Wearout

idata — Sun, 03 Jul 2011 16:50:19 GMT

Blanket,

My office is also responsible for maintaining a research database.

Here's what we have found:

(1) a 2xRAID0 of rotating platters is generally faster, and

contrary to widespread public opinion, the load on each is

roughly 50% over time;

(2) if one member fails, the practical effect is the same

as a single drive failing: the failed drive must be replaced and

the data restored --> "same difference" practically speaking

(3) quality input power is a must, e.g. good UPS;

(4) proper environmental control is also a must:

keeping dust filters clean, keeping ambient temps

under control and within range, etc.

(5) all high-performance HDDs must be installed

in drive cages with active cooling;

(6) the HDDs with 5-year warranties are more reliable,

and the cost per warranty year is usually preferred

as compared to 3-year warranties; e.g. Western Digital

RAID Edition HDDs ("RE");

(7) a key management policy is to EXPECT a failure,

and to have enough backups to recover gracefully;

(8) application of rigorous probability and statistics

urges this conclusion: the conditional probability

that both drives fail, given that one drive of a 2xRAID0 fails,

is extremely small; and, 50% less WRITEs are a major

factor increasing longevity;

(9) data rate is directly proportional to track circumference

on all rotating HDDs, because they maintain the same or

similar recording density on all tracks; thus, more frequently

accessed files should be allocated to "short-stroked" regions

on all HDDs, if possible;

(10) short-stroked drives move the READ/WRITE armature less,

which in turn reduces wear on the armature bearing and

servo-mechanism; and, in combination with RAID-0 arrays,

short-stroking is enhanced in proportion to the number of

RAID-0 members (a 100GB RAID0 partition uses only

the first 25GB worth of tracks on a 4x RAID0);

(11) for temporary files like browser caches and OS swap files,

consider a generous ramdisk: this offloads rotating platters,

further reducing wear on the latter; and, properly configured,

ramdisks can increase real-time performance 15- to 20- TIMES

over rotating platters; cf. my review of RamDisk Plus here:

http://www.supremelaw.org/systems/superspeed/RamDiskPlus.Review.htm http://www.supremelaw.org/systems/superspeed/RamDiskPlus.Review.htm

(DDR3 has become even faster, since that review was written:

and, quad-channel memory access is expected for LGA2011 sockets)

(12) we're still waiting for an answer to our question about TRIM

on OS software RAIDs when members are configured in AHCI mode;

(13) all of the above strongly suggests that the Media Wearout Indicator ("MWI")

on modern Nand Flash SSDS will decline half as fast with a 2xRAID0,

one third as fast with a 3xRAID0, and one-fourth as fast with a 4xRAID0,

simply because of the way "striping" happens on all RAID 0 arrays;

(14) an experiment that Intel should consider doing, and publishing,

is to formulate a proper experimental matrix, and test the real effects

that result from enabling NTFS compression on Nand Flash SSDs,

with and without RAID configurations; SandForce controllers do

real-time compression, reportedly to reduce WRITEs as much as possible;

why not make this the DEFAULT that is performed by the OS, regardless

of the SSD's make or model?

(15) the results of proper experimentation at (14) above should

produce data that will suggest an optimal policy: for example,

perhaps a 3xRAID0 does more to reduce WRITEs to each SSD member

than default NTFS compression, due to the type of compression that

is done in real-time by Windows operating systems (LZ77?):

http://oldwww.rasip.fer.hr/research/compress/algorithms/fund/lz/lz77.html http://oldwww.rasip.fer.hr/research/compress/algorithms/fund/lz/lz77.html

(16) and, given the proliferation of multi-core CPUs, in addition to those

that also support Hyper-Threading, there should be otherwise unused

CPU core resources to perform decompression rapidly in real-time, without

adding too much overhead or causing excessive additional latency

when accessing compressed files; SpeedStep and Turbo Boost

will only help mitigate this overhead, if they are activated to help

accelerate real-time decompression.

Those are just some lessons we've learned here, after many years

at Hard Knocks University.

Hope this helps.

Sincerely yours,

/s/ Paul A. Mitchell, Instructor,Inventor and Systems Development Consultant