Setting Trim _AFTER_ a New Install
mfv at bway.net
Mon May 18 14:18:51 UTC 2015
On Fri, 10 Apr 2015 08:35:41 +0100
Arthur Chance <freebsd at qeng-ho.org> wrote:
> On 09/04/2015 22:27, Warren Block wrote:
> > On Thu, 9 Apr 2015, mfv wrote:
> >> Hello,
> >> I've recently installed FreeBSD r10.1 using bsdinstall and then
> >> loaded a large number of programs and data. After spending
> >> considerable time on the installation I discovered that my SSD has
> >> TRIM which appears to be quite useful. After some investigation I
> >> understand that it is a simple flag that can be set after booting
> >> into single user mode.
> >> I hope my questions are simple:
> >> If TRIM is enabled will it mess up the disk so that everything has
> >> to be reinstalled?
> > No, it will not harm the data. That said, before running tunefs to
> > enable it, make a backup. Always make a backup.
> >> If not, is there anything else I should be aware of?
> > If you used ZFS-on-root, tunefs(8) and TRIM do not apply. ZFS uses
> > TRIM natively now, but I'm not sure if that was in 10.1 or only now
> > in 10-STABLE.
> I'm on 10.1-REL, it's got TRIM in zfs
> root at arthur# sysctl vfs.zfs | grep trim
> vfs.zfs.vdev.trim_on_init: 1
> vfs.zfs.vdev.trim_min_active: 1
> vfs.zfs.vdev.trim_max_active: 64
> vfs.zfs.vdev.trim_max_bytes: 2147483648
> vfs.zfs.vdev.trim_max_pending: 64
> vfs.zfs.trim.enabled: 1
> vfs.zfs.trim.txg_delay: 32
> vfs.zfs.trim.timeout: 30
> vfs.zfs.trim.max_interval: 1
Just wanted to send a long overdue thanks for your help.
I followed Warren's admonition of doing a backup before changing the
flag and was glad I did. Early in the morning, without being
sufficiently caffeinated, I typed newfs rather than tunefs. That, of
course, wiped out the disk. During re-installation the TRIM flag was
set and the old data reloaded. The SSD performance is wonderful.
Let this message be another object lesson of doing backups (and a plug
for the caffeine industry).
Cheers ... __o
Marek (+)/ (+)
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