From: Adams Kevin J (kevin.adams@PHS.COM)
Date: Mon Jul 29 2002 - 16:32:50 EDT
Drew,
My predecessor felt the same way as you and we crashed when a disk with
paging space on it failed.
We mirror all paging space now. We hardly page, but we mirror across
controllers for performance and availability anyway.
Kevin Adams
-----Original Message-----
From: Drew [mailto:apt@dcs-success.com]
Sent: Monday, July 29, 2002 12:39 PM
To: aix-l@Princeton.EDU
Subject: Re: [aix-l] Mirroring rootvg with the mirrorvg command
I thought it was better not to mirror the default dump device which resides
(by default) in hd6. At least as far as AIX 4.3.3 is concerned. If the
default dump device is not on hd6, then it shouldn't matter. I personally do
not mirror the paging space because there is no reason to have another disk
spinning for a mirrored paging space. Why mirror it when you are just taking
up extra resources and adding wear and tear to a disk?
Drew
-----Original Message-----
From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU]On Behalf Of
Green, Simon
Sent: Monday, July 29, 2002 11:10 AM
To: aix-l@Princeton.EDU
Subject: Re: Mirroring rootvg with the mirrorvg command
Way back when, (AIX 4.1?), mirrored paging spaces were not supported. That
is no longer the case.
If you are doing a lot of paging, then by mirroring hd6, rather than having
a separate paging space in its place on the other disk(s), you reduce the
number of disks that paging is spread over, which would affect performance.
However, if that's going to make a significant difference then your system
is already in pretty poor shape and you should get more memory, or more disk
space for extra paging spaces.
My own view is that if you're going to mirror the rootvg then it makes no
sense not to mirror hd6.
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/
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> -----Original Message-----
> From: Ron Schwingel [mailto:rschwing@NDSLTD.COM]
> Sent: 29 July 2002 16:00
> To: aix-l@Princeton.EDU
> Subject: Mirroring rootvg with the mirrorvg command
>
>
> When mirroring the rootvg VG, are there any issues with
> mirroring hd6 also.
> I know a few years ago one of our systems (59H) had some performance
> problems when doing this. I know without mirroring hd6, I
> will not be able
> to boot from the mirror drive, but I will still be able to use any
> additional
> paging spaces I created on the mirror drive until the primary
> is back in
> service, as long as I don't reboot (I could also change the
> default paging
> space).
>
> Is this only an issue on systems doing excessive paging and
> then only if
> using slower processors and disks?
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