From: Green, Simon (SGreen@KRAFTEUROPE.COM)
Date: Thu Jun 27 2002 - 12:33:05 EDT
I think it might be better for you to have multiple paging spaces. If
you're not doing any paging, it doesn't really matter what you do. However,
the fact that you're using 25% of the space suggest that you DO page a
little bit. Using multiple physical disks spreads the load.
But you must decide; maybe you only page occasionally, and it's not worth
the trouble of maintaining multiple spaces.
In answer to your other question, mirroring the paging spaces improves
availability.
If you have a mirrored hd6, on hdisk0 and hdisk1, (assuming they're both
rootvg) then if you lose one of those disks the system will keep running.
If you have two separate, unmirrored disks then failure of either disk will
cause a crash as soon as the system tries to access the paging space on that
disk. (If you're not doing any paging the system can keep going for quite a
while, but it'll die eventually.) If you're going to mirror any volume
group, then you should mirror all paging spaces in it.
Simon Green
Senior Technical Analyst
UNIX and AS400 Services
Philip Morris ITSC-E
Tel: +44 1242 284318
Fax: +44 1242 252501
> -----Original Message-----
> From: Dave.Zarnoch@SUNGARD.COM [mailto:Dave.Zarnoch@SUNGARD.COM]
> Sent: 27 June 2002 17:02
> To: aix-l@Princeton.EDU
> Subject: Re: Problems with paging space
>
>
> Simon,
>
> Thanks!
>
> At this point, The most it appears to use is 25% of each space.
>
> I'll probably consolidate both to form an 8GB hd6.
>
> Thanks!
>
> DaveZ
>
>
>
>
>
> "Green, Simon"
> <SGreen@KRAFTE To: aix-l@Princeton.EDU
> UROPE.COM> cc:
> Sent by: IBM Subject: Re:
> Problems with paging space
> AIX Discussion
> List
> <aix-l@Princet
> on.EDU>
>
>
> 06/27/2002
> 11:45 AM
> Please respond
> to IBM AIX
> Discussion
> List
>
>
>
>
>
>
> There is no point having more than one paging space on a
> single physical
> disk and it can actually reduce performance, (compared with a single,
> larger
> paging space). You should determine how much paging space
> you require in
> total, then distribute that amongst suitable disks, always
> ensuring that
> /dev/hd6 in rootvg is large enough for the system to start.
> Ideally, all
> paging spaces should be the same size, but that is not actually a
> requirement.
>
> Simon Green
> Philip Morris ITSC Europe
>
> AIX-L Archive at http://marc.theaimsgroup.com/?l=aix-l&r=1&w=2
> AIX FAQ at http://www.faqs.org/faqs/aix-faq/
>
> N.B. Unsolicited email from vendors will seldom be appreciated.
>
> > -----Original Message-----
> > From: Dave.Zarnoch@SUNGARD.COM [mailto:Dave.Zarnoch@SUNGARD.COM]
> > Sent: 27 June 2002 16:00
> > To: aix-l@Princeton.EDU
> > Subject: Re: Problems with paging space
> >
> >
> > Thanks!
> >
> > Here's what I have now:
> >
> > Page Space Physical Volume Volume Group Size %Used
> > Active Auto
> > Type
> > paging02 hdisk0 rootvg 4096MB 0
> > no yes
> > lv
> > paging01 hdisk3 vg00 4096MB 21
> > yes yes
> > lv
> > paging00 hdisk2 vg00 4096MB 21
> > yes yes
> > lv
> >
> > There is a lot of disk activity on hdisk3 and hdisk2 due to a
> > DB app and
> > third party
> > app running there
> > rootvg is VERY quiet
> >
> > I think I'll try to:
> >
> > Change the dumpdevice temporarily
> > Remove paging02 (on vg00 Second VG)
> > Deactivate paging00
> > Remove paging00 (on vg00 Second VG)
> > Create hd6 (not mirrored) on rootvg
> > Create paging00 (not mirrored) on rootvg
> > (This way I can utilize the "round robin" method)
> > Deactivate paging01
> > Remove paging01
> > Change the dumpdevice to utilize the space freed
> > on vg00.
> >
> > Does this sound OK?
>
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