morbus2000 at web
Aug 19, 2009, 1:28 AM
Post #1 of 1
(496 views)
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extrem slow performance copy file on drbd
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hi,
Hardware / Software:
two Supermicro Server 8GB RAM, 2xQuadcore Xeon 5x
3ware 9550 Raid 5 with 6*320GB Seagate,
Network for DRBD between the two systems is a direct 10 GB connection (Intel 82598EB 10GbE AF Network Adapter) only for DRBD Sync
SLES 10 SP2, 2.6.16.60-0.39.3-xen #1 SMP x86_64
DRDB 8.2.6
Raid 5 > phy. Disk > LVM > DBBD > LVM > XEN > VBD
one lv on top of DRBD as OCFS2 for the DomUs
we test the following
set
# blockdev --setra 8 /dev/sda (default)
# echo 512 > /sys//block/sda/queue/nr_requests
# echo deadline > /sys/block/sda/queue/scheduler
# echo 20 > /proc/sys/vm/dirty_background_ratio
# echo 60 > /proc/sys/vm/dirty_ratio
copy 2,7GB iso file from /tmp > lv on top of drbd /dev/vgmirror/test - time 7:43 min
then we set read-ahead
# blockdev --setra 16384 /dev/sda (only change)
# echo 512 > /sys//block/sda/queue/nr_requests
# echo deadline > /sys/block/sda/queue/scheduler
# echo 20 > /proc/sys/vm/dirty_background_ratio
# echo 60 > /proc/sys/vm/dirty_ratio
copy 2,7GB iso file from /tmp > lv on top of drbd /dev/vgmirror/test - time 0:35 min
I think thats OK.
now we copy the same file direct on top of drbd - time 3:42 min
then we attach the same phy lv /dev/vgmirror/test to DomU
# xm block-attach 10 phy:/dev/vgmirror/test /dev/xvdb w
copy the *.iso file from Host /tmp > DomU:/mnt which mount to /dev/vgmirror/test
# scp /tmp/*.iso domU:/mnt/
after approximately copy 1GB eth transfer rate goes bck to 10 Mb/s
after approximately copy 2GB -- stalled-- (time 5:09 min)
I don t understand this behavior?
/etc/drbd.conf
-----------------
global {
usage-count yes;
# minor_count 5;
# dialog-refresh 5;
disable-ip-verification;
}
common {
syncer { rate 600M; al-extents 257; }
}
resource drbd0 {
protocol C;
handlers {
split-brain "/usr/lib/drbd/notify-split.brain.sh root";
}
startup {
wfc-timeout 0;
degr-wfc-timeout 120;
become-primary-on both;
}
disk {
on-io-error detach;
max-bio-bvecs 1;
}
net {
allow-two-primaries;
after-sb-0pri discard-zero-changes;
after-sb-1pri discard-secondary;
after-sb-2pri disconnect;
}
on enterprise5 {
device /dev/drbd0;
disk /dev/vglocal/lvlocal;
address 192.168.1.15:7788;
flexible-meta-disk internal;
}
on enterprise6 {
device /dev/drbd0;
disk /dev/vglocal/lvlocal;
address 192.168.1.16:7788;
flexible-meta-disk internal;
}
}
Why is write performance so low?
What else can I do to get better write performance?
help me, please.
Regards
Andreas
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