bdf response is delayed

[Greg Hall]

We have a client system running 10.20 which always has a delay of several seconds in responding to 'bdf' . This isn't really a problem, but it doesn't happen on any other HP systems I work on, and I wonder if it is indicative of an underlying problem.

cheers, Greg

[Alex Glennie]

Hi,

Some possible causes :

1. large buffer cache
2. nfs file system dirty at bdf time
3. heavy system load
4.underlying hw-problem
5.tmplog mount option as opposed to the default delaylog option

Thinks to check / look at :

1.Check bdf process with glance ?
2.dmesg ?
3.sar 1 100 whilst and not while bdf running ?
4.syslog.log
5 run h/w diagnostics ?

[John Palmer]

Hi Greg,

The most common cause of slow bdf response in my experience is when there are a lot of 'dirty' filesytem blocks in the buffer cache.

bdf runs 'sync' as part of its activities so it has to wait while these are flushed to disk.

Does this system have a large buffer cache and a lot of write activity?

Regards,
John

[Greg Hall]

Alex and John,

thanks for your responses. We are investigating buffer pages etc, more from interset than any pressing problem.

cheers, Greg

[Anthony Goonetilleke]

There once a server with similar problems it turned out that file IO was causing BDF to respond slowly

do the following

ps -ef | grep -i cpio
ps -ef | grep -i cp
ps -ef | grep -i find

these commands running can cause bdf to be very slow on a filesystem.

[BONNAFOUS Jean Marc]

bdf can have problem if you mount nfs disks and if that nfs connection doesn't work correctly. In this case umount nsf disk and test again.