Of the 30 servers I have now, only 3 are currently swapping (and not
much). 

Btw: I got the 2 x memory algorithm from IBM and I've been using it for
about 4 years now. I am not having any problems with 1G swap on dasd but
lately have seen many people talking about vdisk as a replacement.

I can get as many mod3 as I want - I just don't know how many.

If I start to use vswitch, would you recommend that I put 500m on dasd
and the other 500m on vdisk (and put a higher priority on the vdisk
swap) ? My users could always use an extra 500m of space.

-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
David Boyes
Sent: Wednesday, February 28, 2007 10:18 AM
To: [email protected]
Subject: Re: Vdisk

> I have one mod9 and 6 mod3 for paging (total pages 5281K) - abo0ut 38%
> used right now. Would this be sufficient ?

Hmm. Without knowing the usage patterns of your system, and not having
perf data, I'd be cautious in saying it's enough for total safety, but
it looks like enough to get started w/o serious risk. Two
questions/observations: 

1) Are your Linuxen using their swap space at all? If so, how
much/often? The answer to "is it enough" depends a lot on this answer.

2) Trade the mod 9 for 3 mod 3s if you can. Additional device addresses
allow CP to initiate multiple simultaneous I/Os, and while CP tries to
get the most bang for it's buck by lining up multiple pages to be
transferred at the same time when it can, the more devices it has to
work with, the better it can manage. If CP has to page hard -- like
flush out a bunch of VDISK pages to satisfy demands to back virtual
storage for guests -- this tends to make a fairly hefty difference IF
you're careful to not land all the devices on the same drawer in your
storage subsystem. 

----------------------------------------------------------------------
For LINUX-390 subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or
visit
http://www.marist.edu/htbin/wlvindex?LINUX-390

----------------------------------------------------------------------
For LINUX-390 subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit
http://www.marist.edu/htbin/wlvindex?LINUX-390

Reply via email to