On Thu, Jul 19, 2012 at 03:04:29AM +0700, Fajar A. Nugraha wrote: > > On the Crucial RealSSD C300 256GB, and from talking to their tech support > > and other folks who happened to have gotten that 'drive' at work and also > > got weird unexplained failures, I'm convinced that even its latest 007 > > firmware (the firmware it shipped with would just hang the system for a few > > seconds every so often so I did upgrade to 007 early on), the drive does > > very poorly without TRIM when it's getting close to full. > > If you're going to edit the wiki, I'd suggest you say "SOME SSDs might > need to use TRIM with dmcrypt". That's because some SSD controllers > (e.g. sandforce) performs just fine without TRIM, and in my case TRIM > made performance worse.
Right. I'm definitely planning on writing that it is controller dependent. By the way, I read that SF performs worse with dmcrypt because: http://superuser.com/questions/250626/sandforce-ssd-encryption-security-and-support 'Using software full-disk-encryption on an SSD seriously impacts the performance of the drive - up to a point where it can be slower than a regular hard disk.' http://c089.wordpress.com/2011/02/28/encrypting-solid-state-disks/ http://www.madshrimps.be/articles/article/965#axzz1FGfzD15q So, really, it seems that one should not buy a drive with a sandforce controller if you plan to use dmcrypt. I haven't found clear data to say which controllers other than sandforce have the same problem. https://docs.google.com/a/google.com/viewer?a=v&q=cache:eyoe3gL10qcJ:www.samsung.com/global/business/semiconductor/file/product/ssd/SamsungSSD_Encryption_Benchmarks_201011.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEEShHEj1jkxdwa7JREmubW6iAyc2RGqQt8MoGxMgQrRNDifoGqTYWjYdaUypnaRtkjKrjiOt1JCr4dDt4ycD2rjWO51PtAo67JvnZGe6Gx1s-9yjkRVYZWsUHZApkjm7dWVzkdQg6&sig=AHIEtbRaViqG4cYC_RYajAW04JRjNhQq6g seems to imply that software encryption on samsung drives (which is what I just got as a replacement for my crucial), does not have the same penalty than you have with the SF controller. But back to the point about "yes, it depends". Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
