Am 15.01.2014 15:34, schrieb Sebastien Han:
Hum the Crucial m500 is pretty slow. The biggest one doesn’t even reach 300MB/s.
Intel DC S3700 100G showed around 200MB/sec for us.

where did you get this values from? I've some 960GB and they all have > 450Mb/s write speed. Also in tests like here you see > 450MB/s
http://www.tomshardware.com/reviews/crucial-m500-1tb-ssd,3551-5.html

Actually, I don’t know the price difference between the crucial and the intel 
but the intel looks more suitable for me. Especially after Mark’s comment.

––––
Sébastien Han
Cloud Engineer

"Always give 100%. Unless you're giving blood.”

Phone: +33 (0)1 49 70 99 72
Mail: sebastien....@enovance.com
Address : 10, rue de la Victoire - 75009 Paris
Web : www.enovance.com - Twitter : @enovance

On 15 Jan 2014, at 15:28, Mark Nelson <mark.nel...@inktank.com> wrote:

On 01/15/2014 08:03 AM, Robert van Leeuwen wrote:
Power-Loss Protection:  In the rare event that power fails while the
drive is operating, power-loss protection helps ensure that data isn’t
corrupted.

Seems that not all power protected SSDs are created equal:
http://lkcl.net/reports/ssd_analysis.html

The m500 is not tested but the m4 is.

Up to now it seems that only Intel seems to have done his homework.
In general they *seem* to be the most reliable SSD provider.

Even at that, there has been some concern on the list (and lkml) that certain 
older Intel drives without super-capacitors are ignoring ATA_CMD_FLUSH, making 
them very fast (which I like!) but potentially dangerous (boo!).  The 520 in 
particular is a drive I've used for a lot of Ceph performance testing but I'm 
afraid that if it's not properly handling CMD FLUSH requests, it may not be 
indicative of the performance folks would see on other drives that do.

On the third hand, if drives with supercaps like the Intel DC S3700 can safely 
ignore CMD_FLUSH and maintain high performance (even when there are a lot of 
O_DSYNC calls, ala the journal), that potentially makes them even more 
attractive (and that drive already has relatively high sequential write 
performance and high write endurance).


Cheers,
Robert van Leeuwen

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