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Solid State Drives . A basic overview Presented by: Steve Jones, Gran-IT Consulting, Inc. SSD Basics . Components Factors affecting Performance Cost Vendors. SSD Components . Circuit Board Flash NAND chips SLC vs MLC 100,000 write cycles vs. 10,000 write cycles
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Solid State Drives • A basic overview • Presented by: • Steve Jones, Gran-IT Consulting, Inc.
SSD Basics • Components • Factors affecting Performance • Cost • Vendors
SSD Components • Circuit Board • Flash NAND chips • SLC vs MLC • 100,000 write cycles vs. 10,000 write cycles • Vast majority of failures NOT cause by “worn-out” NAND memory • Controller • Where the action is • SandForce, Intel, Jmicron, Indilix among leaders
Performance Factors • Controller Performance • TRIM and ITGC • Definition of: TRIM support(PC Magazine)A solid state drive (SSD) feature that improves write speed. SSDs use flash memory, which writes an entire block of storage no matter how few pages within the block are updated. This requires reading and caching the existing data, erasing the block and rewriting the block. If an empty block is available, a write operation is much faster.With support required in both the OS and SSD, the TRIM command enables the OS to inform the drive which blocks are no longer needed. It allows the drive to erase the blocks ahead of time in order to make empty blocks available for subsequent writes • TRIM restores deleted data/cells to ‘virgin’ state; that state receives new data MUCH faster than non-TRIM’ed cells. This slows the degradation of performance as time lapses and drives get more full. • BOTH the OS AND the drive must be TRIM-aware • WIN7 is TRIM-aware; drives vary, but most newer drives with credible controllers are TRIM-aware as well. Check Manufacturer’s website!!
Performance, continued • WinXP and RAID configurations use ITGC which is typcially inferior to TRIM. • Common tweaks • Turn off Defrag • Move temp files to HDD • Turn of indexing • Disable pre- or super-fetching • Move pagefile to HDD
More Performance stuff • PCI E cards improve performance even further by avoiding the 3 (or 6) G/s sata restrictions • Higher end cards are actually RAID-0 over 2 or 4 separate SSD’s claiming ridiculous I/O rates. • Adaptec has a line of RAID controllers with large (32 or 64G) SSD’s used as cache. They also offer RAID cards that can combine HDD’s and SSD’s in the same array.
Drive Failures • VERY difficult to get reliable data from manufacturers. • Consumer-targeted early drive failures were well and loudly documented. • Obviously the trend is toward better reliability. • Ready for ‘Prime-Time’??? • Mind your backups!
References • http://www.zdnet.com/blog/storage/ssd-reliability-lower-than-disks/1222?tag=content;search-results-rivers • http://www.adaptec.com/en-us/products/ • http://www.intel.com/design/flash/nand/ • http://www.hardwarecanucks.com/forum/storage/39762-so-you-wanna-buy-ssd-read-first.html • http://supertalent.com/support/technical.php?open=SSD