Thanks to:
<alan_at_nabeth.cxo.dec.com>
John Speno <speno_at_isc.upenn.edu>
Davis <Davis_at_Tessco.Com>
George
Guethlein <gguethlein_at_giantofmaryland.com>
I had asked where is the "best" place to put a secondary swap mirror set,
full question below.
Paraphrasing the answers the consensus was that there is no performance
penalty or benefit resulting from placement of rootdg.
Alan suggested that since it was unlikely the volume would ever be "shared"
in a cluster sense, rootdg was the place for it.
John thought he remembered reading that secondary swap had to be in rootdg.
George felt the logical place for secondary swap was in rootdg since swap
is a "system" entity, though he adheres to the practical logic of placing
volumes in disk groups named by function.
I quote Davis since he was emphatic: "It is clearly documented that any
swap space defined on LSM volumes /must/
be in the rootdg disk group."
Davis, I don't doubt you, but would you happen to have a reference, since I
can't find one.
I appreciate all your answers, and your speed. If I can, I will try it
both ways tomorrow and see what happens, I am in an empirical mood. But,
you can bet I'll do it first with swapvol2 in rootdg, do a volsave, put the
db files in a safe place, then take it apart and put swapvol2 in another
disk group. I'm not about to mess up a production system with 320 GB of
data across 80 spindles in six disk groups!
Thanks, folks,
Regards
------------------------------------------------------------
Never having added any additional swap space to an LSM configuration,
before, I am faced with the question of where
(in what disk group) to place a mirrored swap volume which I will call
swapvol2 which will be a secondary swap file.
I fail to find any hints in all the documentation available as to which
disk group, rootdg, or a separate one is the best group in
which to place this volume for performance.
It seems to me that since I am using a system where /, primary swap, /usr,
and /var are mirrored and are in rootdg, it would make sense to add my new
swap volume to a new disk group named "moreswap" or something equally
descriptive.
However, I have no information other than that provided by intuition that
it makes any difference in performance or reliability as to which disk
group I place swapvol2. It certainly makes the LSM layout more
understandable to have swapvol2 in a separate disk group, but that's all i
know for sure.
Anyone have any suggestions?
Thanks in advance and of course I'll summarize.
Regards,
Bruce
+--------------------------------------+
Bruce B. Platt, Ph.D.
Comport Consulting Corporation
78 Orchard Street, Ramsey, NJ 07446
Phone: 201-236-0505 Fax: 201-236-1335
bbp_at_comport.com, bruce_at_ bruce.platt_at_
OR, bruce_at_bbplatt.com
Received on Fri Apr 09 1999 - 18:59:53 NZST