On Fri, Feb 15, 2002 at 11:27:06PM +0000, mb/ext3@dcs.qmul.ac.uk wrote:
>
> No. They're all volumes on an ICP-Vortex RAID 5 array, which appears as
> /dev/sda, so fsck serialises it. I'm not sure to go in parallel is a good
> idea, but it is hackable and if you like I'll give it a try.
>
Do a quick hack to your /etc/rc scripts so that the environment
variable FSCK_FORCE_ALL_PARALLEL is set before running fsck, and
you'll probably be much, much happier.
FSCK_FORCE_ALL_PARALLEL
If this environment variable is set, fsck will
attempt to run all of the specified filesystems in
parallel, regardless of whether the filesystems
appear to be on the same device. (This is useful
for RAID systems or high-end storage systems such
as those sold by companies such as IBM or EMC.)
If you have some devices which *should* be checked serially, because
they really are on the same physical device (i.e., you have some other
disk with multiple partitions, you'll need to use the fsck pass number
to keep things running serially). What I *should* do is have some way
of specifying which devices should always have stuff run in parallel,
instead of it being a global on/off switch. Maybe for the next
release....
If it turns out you have too many volumes on your RAID 5 array to run
them *all* in parallel --- i.e., running that many fsck's are causing
you to swamp the I/O bandwidth of your RAID system, or the number of
e2fsck processes is starting to strain your memory, then besides
questioning whether or not your system is unbalanced and you whether
might get huge increases in performance by adding memory (memory is
cheap; adding memory is often the easiest, fastest way to speed up a
system), you can also control the maximum number of fsck processes run
at one time by upgrading to e2fsprogs 1.26, and then setting the
FSCK_MAX_INST environment variable:
FSCK_MAX_INST
This environment variable will limit the maximum
number of file system checkers that can be running
at one time. This allows configurations which have
a large number of disks to avoid fsck starting too
many file system checkers at once, which might
overload CPU and memory resources available on the
system. If this value is zero, then an unlimited
number of processes can be spawned. This is cur-
rently the default, but future versions of fsck may
attempt to automatically determine how many file
system checks can be run based on gathering
accounting data from the operating system if this
environment variable is not set.
Hope this is helpful!!!
- Ted
