From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mikael Abrahamsson Subject: Re: doubts about sdd raid1 and cfs Date: Sat, 13 Jun 2015 22:32:26 +0200 (CEST) Message-ID: References: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Roberto Spadim Cc: Linux-RAID List-Id: linux-raid.ids On Sat, 13 Jun 2015, Roberto Spadim wrote: > hum, but what about the 850 version instead of 840? SSDs have been around for more than 5 years (intel released the X25-M in 2008 according to wikipedia), TRIM has been around for 4-5 years. I have seen so many problems related to TRIM, that I will not use it unless it comes default on from a manufacturer that has tested the entire chain, including hardware and software (my Apple laptop for instance). We have seen TRIM not being NCQ enabled and stalling performance when doing TRIM, we have seen firmware bugs that cause drives to lose data when doing TRIM, we have seen Linux kernel bugs that also caused loss of data. First of all, ask yourself why you want TRIM, understand how it works and if you will benefit, do your research properly, and then enable it. Personally, I overprovision my SSDs instead: http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/whitepaper/whitepaper05.html https://en.wikipedia.org/wiki/Write_amplification#Over-provisioning http://www.seagate.com/gb/en/tech-insights/ssd-over-provisioning-benefits-master-ti/ http://www.edn.com/design/systems-design/4404566/Understanding-SSD-over-provisioning http://www.kingston.com/en/ssd/overprovisioning So I basically leave space on the drive that I don't use. In your case I would only partition 200GB (or even less) of that 240GB drive, and I would run it without TRIM. -- Mikael Abrahamsson email: swmike@swm.pp.se