SSD TRIM support

[amlife]

Hello

I bought an SSD drive today and it says "Native TRIM support (O/S support required)" I was wondering if I can enable this feature on freenas? I'm using version 8.0.4-RELEASE-p2

Thank you

 

[William Grzybowski]

For what purpose are you using the SSD? As the install media for FreeNAS?

 

[amlife]

I'm planning on using it as a write cache for RAID-Z array. as I'm disappointed with my virtual machine performance!

 

[William Grzybowski]

I might be wrong but I think ZFS does not support TRIM

 

[amlife]

I looked at the following post http://forums.freenas.org/showthrea...th-4xWD-Advanced-Format-drives&highlight=TRIM


doing some google-ing it seems that it is supported and it is enabled by default.

I'm at work right now, and I don't have ssh access to my box! I will try and run "camcontrol " against my SSD device when I get home and it see if the TRIM is supported or not.

Thanks

 

[Joshua Parker Ruehlig]

nice, my cache SSD shows trim support as yes! Though this doesn't prove it's on.

I remember in linux there was a way I tested it. You create a file, read the blocks, delete it, reread it, and nothing has changed. then when you check again after a period of time the blocks are all marked as 0's. (that's the filesystem triming it when it finds time.) There was also a way to manually trim the drive with a command, mind you this was all on ext4 but I'll see if I can dig up the thread.

EDIT
found it, thread never concluded if my test proves anything, but I believe this is what's supposed to happen.
http://www.mydellmini.com/forum/my-...-64-gig-mini-9-trim-support-4.html#post172478

 

[amlife]

Can you share how did you find out it is enabled? did you run the camcontrol command?

according to wikipedia "TRIM command will detect and inform (SSD) which blocks of data are no longer considered in use and can be wiped internally", so I think that test actually shows how everything works!

 

[Joshua Parker Ruehlig]

I ran camcontrol and it showed that my ssd supported trim. But this didn't say anything about it being enabled.

I read a bit on freebsd 9 changelog and it looks like they just got TRIM in freebsd's fast filesystem, it made no mention of ZFS so I bet it isn't supported yet.