Messages in this thread | | | From | "Daniel J Blueman" <> | Subject | Re: Kernel 2.2.14, dirty buffers, stalls in interactivity of system/NFS-clients ... | Date | Wed, 29 Mar 2000 00:47:03 +0100 |
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Hi Bryan,
> I cannot figure out what the culprit is. One concern is the fact > that RedHat still ships with bdflush-1.5 and Caldera ships with > bdflush-1.62. And someone mentioned that bdflush has now been > replaced by kflushd (in the kernel?). I have kflushd, kupdate and > kswap all showing up in my ps/top list. /sbin/update reports that > it is from bdflush 1.4, although I have installed the 1.5 RPM.
When init loads the update (bdflush) daemon, it simply exists at the first flush (5s later?), since the kflushd kernel thread is doing the work. That's why you cannot see the updated/bdflush process. I think the version of bdflush you have doesn't matter, in this case.
You'll need to get some parameters tuned though to see better performance. If you can tune the I/O subsystem such that it flushes dirty data every 5s (.'. in a much smaller bursts), since the RAID controller will deal with it asyncoronsouly, it shouldn't cause your system to grind to a halt.
This large flush every 30s may be larger than the write-back buffers in your RAID controller, such that the whole process becomes disk I/O bound, not PCI bus I/O bound. As said, try reducing the time interval to 5s - you want a quiescent flow of data onto your disks, not too bursty.
- Dan __________________________ Daniel J Blueman Undergraduate - BSc Computing Science UMIST university - Manchester Direct line: 0161 933 3569 Mobile: 07775 583766 Email: daniel.j.blueman@stud.umist.ac.uk SMS: daniel.j.blueman@sms.genie.co.uk
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