Are your disk LVM? If LVM what size volumes did you use to create them. If LVM,
is PAV support enabled? Could you be bottlenecking because of lack of
PAV?
"Brandt, Mark H" <[EMAIL PROTECTED]>
Sent by: Linux on 390 Port
<[email protected]>
To
[email protected]
cc
08/17/2006 12:08 PM
Subject
Re: I/O
wait times -vs- Linux memory
Please respond to
Linux on 390 Port <[email protected]>
Not enough controller cache ?? Minidisk cache turned off ..?? - the
best i/o is the one you don't do ..
Mark
-----Original Message-----
From: Richard Troth [mailto:[EMAIL PROTECTED]
Sent: Thursday, August 17, 2006 10:03 AM
To: [email protected]
Subject: Re: I/O wait times -vs- Linux memory
3390
Vendor should not matter; these are on an EMC frame.
What would bog Linux I/O to 3390s?
-- R;
----- Original Message -----
From: Dave Jones [EMAIL PROTECTED]
Sent: 08/17/2006 12:24 PM
To: [email protected]
Subject: Re: I/O wait times -vs- Linux memory
Rick, what kind of Linux i/o are you doing? To real 3390s? To SHARKs
looking like a 3390? To some sort of SCSI attached disk?
DJ
Richard Troth wrote:
> We're looking at some high I/O wait times for a certain database. One
> engineer has suggested that we add memory to Linux to speed things up.
> I don't see it. Does adding RAM to Linux help its I/O throughput?
>
> We've put a lot of effort into sizing our Linux guests (all hosted by
> z/VM 5.2) to that magical point between guest-level paging and excess
> guest memory use, so some of us resist the thought of adding
> real-to-Linux memory. I seems obvious that adding RAM would let any
> access method do more buffering, but we want to avoid some of that
> buffering because Linux gets carried away with it, correct?
>
> Thoughts? Thanks!
>
> -- R;
>
>
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