Adding to the list, there is still an mtime bug when using write-behind
even without io-threads. It occurs on (big clue!) files with sizes evenly
divisable by 4096 in my AFR/unified setup:
-rw-r--r-- 1 root root 4096 2007-04-28 16:01 /scratch/usr/src/linux-headers-2.6.15-28/include/net/genetlink.h
-rwxr-xr-x 1 root root 12288 2007-04-28 15:54 /scratch/usr/bin/last
-rwxr-xr-x 1 root root 12288 2007-04-28 15:54 /scratch/usr/bin/aseqnet
-rw-r--r-- 1 root root 528384 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/all-universe.db
-rw-r--r-- 1 root root 12288 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/all-multiverse.db
-rw-r--r-- 1 root root 12288 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/i386-restricted.db
-rw-r--r-- 1 root root 135168 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/i386-multiverse.db
-rw-r--r-- 1 root root 12288 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/all-restricted.db
-rw-r--r-- 1 root root 135168 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/all-main.db
-rw-r--r-- 1 root root 4198400 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/i386-universe.db
-rw-r--r-- 1 root root 1052672 2007-04-28 15:54 /scratch/usr/share/command-not-found/programs.d/i386-main.db
-rw-r--r-- 1 root root 65536 2007-04-28 15:53 /scratch/usr/share/samba/valid.dat
-rw-r--r-- 1 root root 61440 2007-04-28 15:57 /scratch/usr/lib/python2.5/distutils/command/wininst-7.1.exe
-rw-r--r-- 1 root root 61440 2007-04-28 15:57 /scratch/usr/lib/python2.5/distutils/command/wininst-6.exe
-rw-r--r-- 1 root root 61440 2007-04-28 15:55 /scratch/usr/lib/python2.4/distutils/command/wininst-7.1.exe
-rw-r--r-- 1 root root 61440 2007-04-28 15:55 /scratch/usr/lib/python2.4/distutils/command/wininst-6.exe
-rw-r--r-- 1 root root 4096 2007-04-28 15:57 /scratch/usr/lib/gettext/msgfmt.net.exe
-rw-r--r-- 1 root root 8192 2007-04-28 15:57 /scratch/usr/lib/GNU.Gettext.dll
-rw-r--r-- 1 root root 143360 2007-04-28 15:56 /scratch/usr/lib/libgc.so.1.0.2
These files have wrong mtimes on both nodes in the AFR, not just one or
the other. It resulted from a simple "cp -a" of my /usr directory.
Thanks,
Brent
On Fri, 27 Apr 2007, Brent A Nelson wrote:
A couple of more bugs observed today:
1) stat-prefetch still causes glusterfs to die on occasion. I can reproduce
this with a bunch of clients doing a du of a complex directory structure; out
of 8 clients du'ing simultaneously, one or two will die before the du
finishes (glusterfs dies). This is probably the same thing I've reported
before about stat-prefetch, but I was hoping io-threads might have been
responsible (it wasn't).
2) NFS reexport is somehow triggering a really rapid memory leak/consumption
in glusterfsd, causing it to quickly die. On the NFS client, I did a du of
an Ubuntu Edgy mirror, which worked fine. Then I did multiple cp -a's of a
simple 30MB directory, which causes rapid memory consumption on the
glusterfsd of node1 of an AFR. It soon dies (before it does the sixth copy),
along with the NFS-exported glusterfs client (running on node1, as well).
This occurs in a simple mirror with storage/posix and protocol/server on the
server and protocol/client, cluster/afr, performance/read-ahead, and
performance/write-behind on the client.
Thanks,
Brent
On Fri, 27 Apr 2007, Brent A Nelson wrote:
Hmm, it looks like io-threads is responsible for more than just mtime
glitches when used with write-behind. I just found that the problems I had
with NFS re-export go away when I get rid of io-threads (plus, now that I
can enable write-behind, the NFS write performance is far better, by at
least a factor of 5)!
It looks like I'll be switching off io-threads for now, and turning on all
the other performance enhancements.
Thanks,
Brent
On Fri, 27 Apr 2007, Brent A Nelson wrote:
On Thu, 26 Apr 2007, Anand Avati wrote:
Brent,
I understand what is happening. It is because I/O threads lets the
mtime overtake the write call. I assume you have loaded io-threads on
server side (or below write-behind on client side).
Yes, I have io-threads loaded on the server. This occurs when I load
write-behind on the client.
I could provide you a temporary 'ugly' fix just for you if the issue is
critical (until the proper framework comes in 1.4)
It would be worthwhile if the temporary fix is acceptable for the 1.3
release (otherwise, you'll need a warning included with the release, so
that people enabling io-threads and write-behind know what to expect), but
don't waste your time if it's just for me. Push on to 1.4 and the real
fix; I'll just leave write-behind disabled for now.
Many Thanks,
Brent
