I've read that SSD TRIM is now supported in the recent kernels with ext4 too (see How to enable TRIM? ).
Is it OK/safe to enable TRIM when having a) LVM b) RAID1+LVM?
Thanks!
I've read that SSD TRIM is now supported in the recent kernels with ext4 too (see How to enable TRIM? ).
Is it OK/safe to enable TRIM when having a) LVM b) RAID1+LVM?
Thanks!
Device Mapper based RAID e.g. via dmsetup
does support TRIM MD raid e.g. via mdadm
does not support TRIM.
http://www.redhat.com/archives/linux-lvm/2010-October/msg00066.html
This might have changed, but a quick grep of the oneiric kernel (git grep REQ_DISCARD drivers/md)
doesn't show any specific support in the MD code for discards. It might be worth searching the MD RAID mailing list to see how this has progressed.
Speaking from experience, I am not a big fan of using DM for managing RAID sets, the tools are kinda cumbersome and basic admin tasks are a burden; and so is recovering a failed RAID. If you want to take the plunge I strongly recommend you model the setup in a VM so you can become accustomed with the toolset's ins and outs. BTW, don't get confused by dmraid
, that's for fake raid only.
http://mbroz.fedorapeople.org/talks/DeviceMapperBasics/dm.pdf