Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hello,
Here I have a two nodes setup:
- CentOS 5.4 x64
- DRBD 8.3.2 (CentOS RPM)
- kernel 2.6.18-128.7.1.el5xen
- Dell PE1950
- Quad-Core Xeons
- 32GB of memory
- PCI NIC Intel 82571EB (e1000)
- Connected directly with a crossover cable.
Each server is a Xen host and only has 512MB of memory reserved for dom0.
DRBD resources appear to slow down or hang during a resync and
apparently during normal operations too. During a rsync, we can clearly
see the sync speed drop to a crawl for 1-2 seconds both in /proc/drbd
and when using a network monitoring tool such as iptraf.
These slowdowns appear to be related to the kernel panics we are having
on this cluster.
Any ideas what might cause this?
Anything you would suggest tweaking in our config?
Is 512MB RAM enough for DRBD to function properly?
We don't mind loosing a bit of performance for more stability :)
# drbdsetup /dev/drbd0 show
disk {
size 0s _is_default; # bytes
on-io-error detach;
fencing dont-care _is_default;
no-disk-barrier ;
no-disk-flushes ;
no-md-flushes ;
max-bio-bvecs 0 _is_default;
}
net {
timeout 60 _is_default; # 1/10 seconds
max-epoch-size 8192;
max-buffers 8192;
unplug-watermark 128 _is_default;
connect-int 10 _is_default; # seconds
ping-int 10 _is_default; # seconds
sndbuf-size 131070 _is_default; # bytes
rcvbuf-size 131070 _is_default; # bytes
ko-count 0 _is_default;
cram-hmac-alg "sha1";
after-sb-0pri disconnect _is_default;
after-sb-1pri disconnect _is_default;
after-sb-2pri disconnect _is_default;
rr-conflict disconnect _is_default;
ping-timeout 5 _is_default; # 1/10 seconds
}
syncer {
rate 33792k; # bytes/second
after -1 _is_default;
al-extents 1801;
verify-alg "crc32c";
}
protocol C;
_this_host {
device minor 0;
disk "/dev/sda6";
meta-disk internal;
address ipv4 10.11.1.1:7788;
}
_remote_host {
address ipv4 10.11.1.2:7788;
}
Regards,
--
Jean-François Chevrette [iWeb]