John W Colby
jwcolby at gmail.com
Wed Mar 12 10:21:14 CDT 2014
One of the magazines did a reliability test where they continuously wrote to a broad array of SSDs testing for failures. At the time the article was written the SSDs had all stood up to 600 TB of writes with no failures. Some of them (The Samsung IIRC) started having to mark bad blocks and use spare blocks however we are talking 600 TB here. http://techreport.com/review/24841/introducing-the-ssd-endurance-experiment/5 http://us.hardware.info/reviews/4178/10/hardwareinfo-tests-lifespan-of-samsung-ssd-840-250gb-tlc-ssd-updated-with-final-conclusion-final-update-20-6-2013 Additionally I have a somewhat unique situation. My databases are "read mostly". The tables which hold the marketing info fields are never updated. Once I get them written to disk I will read from them TONS, but never again write to them. The address records do get read monthly (exported to CSV for processing) but less than 2% of the people move on a monthly basis and I perform updates of only those 2%. So my database SSDs really don't get written all that much, probably less than your desktop drive would. One critical thing to understand is that the controller inside each SSD performs wear leveling. So if you have "static"data, i.e. data that is not written to often or at all, the controller itself will move that static data around to allow other dynamic data to "use" the areas not yet written very often. So basically, before it starts to fail, EVERY cell will be worn down, NOT just a certain area "used a lot". From the perspective of Windows, the location on disk is entirely masked, it has no idea in what "sector" or low level nand location any data is located. Having read several of these "let's test till they fail" articles, I am pretty much convinced (as are the testers) that these drives have a VERY long lifetime. Of course this depends heavily on the application obviously, but in real life very few applications write continuously to a drive. And finally, up to this point I have used a RAID (on the server) which also stripes the data, so that the writes I do perform are spread over several physical disks. And finally, each of my database are backed up to rotating media just prior to performing the monthly update, so if the entire raid array took a dump, I could simply pull the data from last month. With very few exceptions, the only change from last month is the address update process which I can just restore last month and rerun the address updates to be current again. I have been very happy with the SSDs; to this point I have never had a failure. I do have a pair of 120gb (OLD) SSDs in Raid0 which I use for temp dbs, which I am about to replace. Mostly I am replacing them simply because a pair of 500G drives are newer / faster / even more reliable and of course much larger storage size. John W. Colby Reality is what refuses to go away when you do not believe in it On 3/12/2014 10:43 AM, Bill Benson wrote: > John, > > I read in the reviews of the Samsung, that the Pro has a 2 year differential > in the warranty versus the EVO, and that the technology is different / more > reliable. I am surprised that was not a factor for you since you seem to > keep your hardware a long time. Are you planning to upgrade SSDs more > regularly? > > I have recently begun experimenting with VirtualBox by Oracle ... I cannot > add a single one of my DELL drivers to the Win-7-64 OS I downloaded and > installed from MSDN. > > DELL won't support me. Oracle won't support me, and MS won't support me. > > Talk about 3rd party hell. > > BTW I saw another super cheap buy in the link you sent, the WD USB 3.0 > drive... I just can't remember if it was 2 Seagates that started > clicking/clucking and then became unreadable, within 2 months of one another > and about a year after I bought them (just out of warranty) with Geek Squad > taking them apart and could not get any information off them... or WD. Until > I can remember (*IF* I can remember) I will not buy another USB drive from > either of them lol. How's that for consumer lunacy. > > --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com