Is there a maximum to the size of the cache under 4.25D ?
I have a database application that I need to try to speed up.
I am running a 7200 rpm SCSI disk with an adaptec 2940uw controller.
I am running the drivers [ Fsys & Fsys.aha7scsi ] with default options.
I may have up to 40 processes trying to read/write to the disk at the same
time.
The database has many smaller and a few large (1 gig) files.
Besides beefing up the hardware,
which switches could I play with to give me the best results?
-Glenn Sherman
I have used 64MB for cache, but I’ve heard of others using >256MB.
If you use -a and a big -d and -A you can speed things up noticeably
albeit with some risk if you are subject to random re-boots. Note
that with a big -d ( > 10 secs ? ), a large cache and an extended
series of writes, you may get a “stall” when Fsys decides it’s time
to flush its cache to disk. During that time, which can be much
greater than the writeback delay, Fsys is quite unresponsive to
disk accesses such as spawning a prog.
If you are doing mostly reads, stick with small -d and don’t use -a.
Richard
Glenn Sherman wrote:
Is there a maximum to the size of the cache under 4.25D ?
I have a database application that I need to try to speed up.
I am running a 7200 rpm SCSI disk with an adaptec 2940uw controller.
I am running the drivers [ Fsys & Fsys.aha7scsi ] with default options.
I may have up to 40 processes trying to read/write to the disk at the same
time.
The database has many smaller and a few large (1 gig) files.
Besides beefing up the hardware,
which switches could I play with to give me the best results?
-Glenn Sherman
The -a option to Fsys would yield a performance improvement on write (at
the expense of fault tolerance).