Yves Dorfsman wrote: > Tracy Reed wrote: > >> Also consider that when a SATA drive dies your data is gone. When an >> SSD drive dies as a result of too many writes it just goes >> read-only. Vastly different "failure" modes which you may want to >> consider if weighing MTBF. I know which one I prefer. >> > > Would you trust a drive that fails on write ? > What if it started to fail in the middle of writing a block ? Or it could > write a journal entry but not the actual data, etc... ? >
Doesn't work that way. Think about the mapping of bad blocks in traditional drives. Your drive doesn't fail just because a particular block fails. Same story. I recently came across the following article about SSD's and "write endurance" -- http://www.storagesearch.com/ssdmyths-endurance.html. In particular, some ways down that article, he does a calculation assuming a rogue data recorder that writes to the drive at maximum sustained speed constantly. The result he comes up with for the particular make, model & size of drive he is looking at comes out to 51 years before the drive hits its write endurance limit. That was in March 2007. Technology gets better. Apple has been delivering the MacBook Air with an SSD drive since January 2008. On a more enterprise level, Sun introduced their open storage systems (the 7000 series) last year and has been selling them with SSD drives configured for the ZFS write intent log. You can configure them with just about any combination of regular drives and SSD drives and have the ZFS configured to use them to provide the best performance. I don't think you would be seeing those kinds of applications if the expectation was routine catastrophic failure in just a couple of years. -- --------------- Chris Hoogendyk - O__ ---- Systems Administrator c/ /'_ --- Biology & Geology Departments (*) \(*) -- 140 Morrill Science Center ~~~~~~~~~~ - University of Massachusetts, Amherst <[email protected]> --------------- Erdös 4 _______________________________________________ Tech mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
