[zfs-discuss] Re: disappearing zvols
Fajar A. Nugraha
list at fajar.net
Fri Apr 20 01:45:13 EDT 2012
On Fri, Apr 20, 2012 at 11:20 AM, Darik Horn <dajhorn at vanadac.com> wrote:
> This seemed like an easy optimization, but no dice. I tried to
> improve performance by putting the dataset name in a sysfs attribute
> on the zvol device.
> The current udev rule is slow at system start because it calls an
> external program for each node:
I wonder how much of the slowness-and-high-load is due to "external
program" on zfs part.
Since native udev rules (e.g. 60-persistent-storage.rules) also use
external program (scsi_id), I imagine udev developers had considered
using external program to be good enough. Then again, it might be part
of a flaw in default udev rules, which would cause "normal" linux
distros to be unsuitable to handle several hundred block devices, with
or without zfs.
> Unfortunately, the necessary Linux kernel infrastructure is restricted
> and cannot be used by the ZFS driver:
> FATAL: modpost: GPL-incompatible module zfs.ko uses GPL-only symbol
The gory, historical, details on why an external program was chosen:
More information about the zfs-discuss