Re: [Xen-users] Trim support for domU

[Casey DeLorme <cdelorme@xxxxxxxxx>]

I have been using a SSD with Xen 4.2 for 6 months.  I am running on Debian Wheezy Dom0, and a compiled Kernel 3.4.4.

Trim required not only the appropriate kernel, but the discard flag in fstab, and only for compatible file systems (Ext4 being one).

My SSD has /boot/efi and /boot partitions, the rest is LVM, and I have Ext4 for my /home and / (root) partitions with discard flag added manually to /etc/fstab.  This appears to be working.

For virtual machines I have an HVM Windows which without GPLPV drivers appears to have recognized that it was running on a SSD (well a LV on an SSD), as it had Auto Disk Defrag turned off.  So HVM Windows appears to support trim.

I have been running a Debian Squeeze HVM DomU for web development testing, and for stability I had not added trim.  I also have been running a pfSense HVM DomU (FreeBSD) but I have not checked whether it supports trim either.

On Sun, Jul 8, 2012 at 11:25 PM, Liwei <xieliwei@xxxxxxxxx> wrote:

Hi list,
    Recently we've been thinking of adding SSDs into some of our domU
VMs to boost application loading times. Looking around, it seems that
information about trim support in various configurations is sparse at
best.
    The only clear confirmation I could find is that trim is supported
in PV domU on Linux kernels 3.1 and above, but only if dom0 has kernel
3.1 and above as well.
    So paravirtualised Linux domUs are fine for the upgrade, but what
about other configurations?
        1. Non-PV Linux domUs?
        2. Non-PV BSD domUs?
        3. PV BSD domUs?
        4. Windows domUs?
        5. Windows domUs with PV drivers?
        6. Other non-PV configurations?
    Perhaps it'd be great to clear everything up now.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users