Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Some clarifications:
On Sun, 18 Jan 2004 22:18:51 -0500
george young <gry at ll.mit.edu> threw this fish to the penguins:
> [drbd-0.6.10, Suse 8.2 x86 linux 2.4.20-4GB-SMP, 2 nodes, pvt 100Mb net]
> I have two nodes, pig-app and pig-db. Default config is that pig-app has
> the active copy of /home(36GB), pig-db has /db(1GB), each DRBD mirrored to
> the other. If and *only if* an administrator decides that one node is
> down, she runs a script on the remaining node to take over the other's
> file system (and switch ip's around so users get the new host). I'm
> having trouble getting the right drbd commands for this script. I also
> see very slowww syncing time...
> Both are are reiser file systems.
> There is a private 100Mbit ethernet between the two nodes.
The 100Mb private net seems healthy: tar-rsh-tar gets me 7.5MB/s.
Without the tar and fs overhead I get 7.9MB/sec.
With --sync-min=10M and fsckcmd=/bin/true and separate --sync-groups
and removing the disconnect/net pair of commands, I get 1h44m sync
for the 36G partition, i.e. 5.8MB/s. It would be nice to do 20%
better, but clearly not a lot faster until I get gigabit ethernet.
> I use the HA-Linux "IPaddr" script, but heatbeat is *not* enabled.
>
> Here's my script for pig-app to grab the /db filesystem from pig-db:
> ------------------------------------------------------------
> if ping -c 1 pig-db; then
> rsh -n pig-db /usr/local/etc/ha.d/resource.d/datadisk drbd_db stop &
> sleep 30
> fi
I think I had put these in hoping to avoid a long sync delay.
I'll take them out.
#> /sbin/drbdsetup /dev/nb1 disconnect
#> /sbin/drbdsetup /dev/nb1 net 10.0.0.115:7789 10.0.0.114:7789 C
> /usr/local/etc/ha.d/resource.d/datadisk drbd_db start
I *do* start other services in this script: samba, postgres,
and the roving service IP addresses were omitted here for brevity.
> ------------------------------------------------------------
> I'm trying to assure that I don't get into a 2-hour long sync while
> users are screaming. After correcting the problem, I can revert
> off-hours, so that time is not critical.
> Does this script make sense? How could it be better?
>
> I am also frustrated that it takes 2 hours to sync 36G over a 100Mbit
> private net. That's a rate of about 5 Mbytes/sec. Disks on both hosts
> are fast hardware raids. Am I missing something?
>
> Below is my(common) drbd.conf:
> ------------------------------------------------------------
> resource drbd_home {
> protocol = C
> fsckcmd = fsck -p -y
I'll change this to /bin/true
> disk {
> disk-size = 36707364k
> }
> net {
> sync-min = 500k
I'll change this to sync-min=10M
> sync-max = 100M # maximal average syncer bandwidth
> tl-size = 5000 # transfer log size, ensures strict write ordering
> timeout = 60 # 0.1 seconds
> connect-int = 10 # seconds
> ping-int = 10 # seconds
I'll add sync-group=1
> }
> on pig-app {
> device = /dev/nb0
> disk = /dev/rd/c0d0p5
> address = 10.0.0.115
> port = 7788
> }
> on pig-db {
> device = /dev/nb0
> disk = /dev/rd/c0d2p1
> address = 10.0.0.114
> port = 7788
> }
> }
> resource drbd_db {
> protocol = C
> fsckcmd = fsck -p -y
> disk {
> disk-size = 1052184k
> }
> net {
> sync-min = 500k
> sync-max = 100M # maximal average syncer bandwidth
> tl-size = 5000 # transfer log size, ensures strict write ordering
> timeout = 60 # 0.1 seconds
> connect-int = 10 # seconds
> ping-int = 10 # seconds
I'll add sync-group=2
> }
> on pig-app {
> device = /dev/nb1
> disk = /dev/rd/c0d0p3
> address = 10.0.0.115
> port = 7789
> }
> on pig-db {
> device = /dev/nb1
> disk = /dev/rd/c0d0p1
> address = 10.0.0.114
> port = 7789
> }
> }
>
--
"Are the gods not just?" "Oh no, child.
What would become of us if they were?" (CSL)