[DRBD-user] DRBD on LVM on SoftwareRaid on SSD...

Lars Ellenberg lars.ellenberg at linbit.com
Wed Nov 2 17:41:25 CET 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Wed, Nov 02, 2011 at 05:22:43PM +0100, Arnold Krille wrote:
> On Wednesday 02 November 2011 11:35:37 Robert Krig wrote:
> > So my question is, since the actual Harddrives are SSDs, are there any
> > special options I would have to use, considering that I'm using SSDs for
> > this purpose.
> > The DRBD block device is mounted as ext4 with the discard option.
> > But will the fact that these are SSDs, translate through all the layers?
> > DRBD, LVM, SWraid?
> > 
> > Drbd is supposedly SSD aware, but does that still work when drbd is not
> > directly formatted onto /dev/sda or /dev/sdb?
> Afaik, software-raid on linux doesn't know about ssd-features.
> LVM2 does know about ssd and doing the mirroring in lvm will give you all the 
> benefits you are looking for.

Unfortunately DRBD does not yet know about DISCARD either.
Not much, anyways.

We still need to figure out how to best handle various cornercases,
and it has not yet been a top priority to support it.
Currently, you won't get DISCARDS through.

: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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