From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <93911a18f997c5389110851f30a25fc0@quanstro.net> From: erik quanstrom Date: Mon, 3 Aug 2009 00:38:02 -0400 To: john@degood.org, 9fans@9fans.net In-Reply-To: <4A7646DB.7020403@degood.org> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Subject: Re: [9fans] just an idea (Splashtop like) Topicbox-Message-UUID: 361e2e68-ead5-11e9-9d60-3106f5b1d025 > For the Intel SSD one must also consider: > > > 3.5.4 Write Endurance > > 32 GB drive supports 1 petabyte of lifetime random writes and 64 GB drive supports 2 petabyte of lifetime random writes. > That is equivalent to writing the capacity of the SSD 31250 times. At > the specified random 4K write rate of 3300 IOPS one could wear out the > SSD in 876 days. Non-random writes could cause more rapid wear, > depending on their pattern and the wear leveling algorithms in the SSD. do you think this is a serious limitation? by my calculation, assuming that you read everything written at least once and 10x faster read than write leading to 3300 iops taking 1.1s 1000^5 bytes /(3300 s^-1 * 1.1^-1 * 4*1024 bytes)/86400s/day = 942 days this is 153 days short of the product lifetime. by the way, one would expect ~8 ures during this test (8e15 bits/1 ure/1e-15 bits). (http://download.intel.com/support/ssdc/hpssd/sb/english_ssd_3_year_warranty.pdf) do you really think its reasonable that someone could run this drive at 100% of capacity for 2½ years? even allowing for shipping and installation time will get you pretty close to the warranty. can you think of how this could be done with a plan 9 application that's doing something useful? it's hard to know if non-random writes create more wear than intel specifies or not. strictly sequential i/o should create similar wear because 16 4k writes can be combined into one flash cycle and 16*3300*4k is about 216 mb/s. so i don't see how you can get in more flash cycles than 3300/s and increase the wear rate. - erik