Am 16.12.2011 05:15, schrieb Shyam Prasad N:
On 12/16/2011 09:14 AM, Chester wrote:
On Thu, Dec 15, 2011 at 8:19 PM, Fajar A. Nugraha<l...@fajar.net>
wrote:
On Fri, Dec 16, 2011 at 1:49 AM, Tobias<tra...@robotech.de> wrote:
Hi all!
My BTRFS-FS ist getting really slow. Reading is ok, writing is slow
and
deleting is horrible slow.
There are many files and many links on the FS.
# btrfs filesystem df /srv/storage
Data: total=3.09TB, used=3.07TB
this is ... what, over 99% full?
The slow down is normal, somewhat. Same thing happens on zfs, which
became slower when usage is above 80-90%.
I don't think "total" actually means "total space available" it
increases as you use up more space.
Chester is right, the disk is a 8TB Array - the fs is less than half filled.
Wouldn't it be more valuable to first collect enough info/data to
debug the problem, before suggesting ways to get out of this situation?
AFAIK, the slowness could be due to several reasons:
1. Slow disk writes.
That depends on what is slow for you. Its a SATA-Disc-Array so good
linear Read/Write and low IOPs (compared to SSDs or SAS-Discs)
2. Too many things to commit to the disk.
I think there should be very little data to write/commit when deleting
files. Remember: writing is slow, but acceptable - deleting is the problem
3. Too many things to do to actually accomplish the writes.
I just do rm -rf xxx. What has BTRFS to do to actually delete a file or
directory?
Is there some sort of profiling which we can enable, which can give us
info about the speeds and quantities of read and write traffic on the fs?
Aren't there btrfs statistics that we can print out, which can give us
these info? If not, we probably should think about adding some.
Good question - maybe a dev can say?
Tobias
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