If they are connected to a regular LSI controller they won't get TRIM commands... How do you know they need TRIM? Thanks, Bar. On Wed, Jul 11, 2012 at 7:21 PM, Bernd Schubert <bernd.schubert@xxxxxxxxxxx> wrote: > On 07/11/2012 01:27 PM, David Brown wrote: >> On 07/11/2012 12:55 AM, Bar Ziony wrote: >>> Hi, >>> >>> I wasn't able to find any information about it after searching for >>> hours - Does mdadm supports sending the TRIM command to SSDs, if using >>> the right filesystem with the 'discard' flag? >>> If it does support it, from what kernel version it is? >>> >>> Thank you, >>> Bar. >> >> The big question here is /why/ would you want TRIM support? In many >> circumstances it leads to slower operations, and for SSDs from the past >> couple of years it is almost entirely superseded by the SSD's own >> garbage collection. >> >> So while there certainly has been some work done on TRIM and md raid, it >> is not a priority as it is of questionable benefit. You might find some >> operations are a little faster for older SSDs if you use TRIM, but your >> metadata operations will be a lot slower. >> >> Your best bet is just to make sure you only buy SSDs that are at least >> half decent, and don't worry about TRIM. > > > Well, we do have not-so-old Intel 510 SSDs on our institute cluster and > these SSDs really need trim. And it gives us quite some headache for > some reason (reason is an annoying LSI SAS controller they are connected > to). > > > Cheers, > Bernd -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
