Re: doubts about sdd raid1 and cfs

[Mikael Abrahamsson <swmike@swm.pp.se>]

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