Subject: Re: File Copy Performance tweak needed (wanted)
From: andrew morgan (morgan@orst.edu)
Date: Thu Apr 06 2000 - 18:33:11 EDT
On Thu, 6 Apr 2000, Chip Mefford wrote:
> Linux RH 6.1 intel.
>
> netatalk 1.4b2+asun2.1.3
>
> When copying any file of any significant size to the netatalk
> server, the copy will begin on the mac, proceed, then pause for
> a time, then either finish, or procced and pause again, then
> finish.
>
> Just from watching the file server, during the actuall copy, there
> is pretty much no disk activity, then during the pause, the
> disk gets real busy, then during the next phase of the copy
> the activity drops until the next pause, then the disk gets
> busy and so on.
>
> I was wondering if there was some kind of buffering going on
> that I can have some control over.
I doubt netatalk or linux are buffering that much data or that they would
cause this kind of problem. Do you have a caching SCSI or RAID
controller? We see something similar to this behavior, although it is not
very pronounced, with large writes to our RAID 5 array. Whenever it
decides it has to write out all the changes and calculate the parity,
there is a pause for a few seconds. Setting you cache to write-back
instead of write-through can help, but make sure you are aware of the
consequences.
Andy
This archive was generated by hypermail 2b28 : Wed Jan 17 2001 - 14:30:25 EST