I am assuming that you are using DB2 in DMA ather than SMS. If in DMS I would (based upon some ancient classes I took on DB2) consider using small volumes, especially segregating indices, for both the locality of reference *and* the ability to tune each volume's caching by the DBMS (DB2).
Now I might be a little bit out of date, but I recall, in DB2's "DMS" logical volumes, were usually in character rather than block devices. I feel particularly out of date given that I don't recall disk volumes becoming available as character devices in Linux unless this is a feature of the logical volume manager. Am I getting stale? -soup On Tue, Mar 22, 2011 at 10:41 AM, Samir Reddahi <[email protected]>wrote: > Hi, > > thanks guys for the info. Maybe a little more clarification on the > situation. > > The logical volume will be used for a heavily used DB2 production machine, > so I'm looking for a maximum I/O throughput. > Extending is not an issue here. This is just a temporary situation till we > migrate to SLES11 to use hyperPAV on MOD 27 disks. Meanwhile a lvextend is > very unlikely. The reason why I can't wait for the migration to SLES11 is > because we are in the middle of a SAN migration. > > I should definitely test the situation with different stripecounts > considering the I/O channels. > > > best regards > *Samir Reddahi* > > [image: Footer] > > > > From: "Frank Schwede, LSY" <[email protected]> > To: [email protected] > Date: 22/03/2011 13:58 > Subject: AW: maximum stripes in a logical volume > Sent by: Linux on 390 Port <[email protected]> > ------------------------------ > > > > Hi, > > > http://www.linuxtopia.org/online_books/rhel6/rhel_6_lvm_admin/rhel_6_lvm_stripe_extend.html > > > > My thoughts: > > · your stripecount also defines the count of disks you need for > proper extending. > > · performance wont be increased much, if you define more stripes > than I/O channels (so maybe 8 or 16 is enough) > > · maybe you should think about creating Model27 or Model54 disks > and let the subsystem support the OS in this case > > · And maybe create a linear LVM and use PAV "parallel access to > volume" with those M27/M54 > > > > br > > Frank > > > > Von: Linux on 390 Port > [mailto:[email protected]<[email protected]>] > Im Auftrag von Samir Reddahi > Gesendet: Dienstag, 22. März 2011 11:17 > An: [email protected] > Betreff: maximum stripes in a logical volume > > > > I created a volume group with 144 MOD-9 disks. Usually when I create > logical volumes, I create them with stripes equalling the number of volumes > in the volume group. > > But apparently you can only define a maximum of 128 stripes on a logical > volume. > What do I do best in this situation? > Is it OK to use the maximum 128 for a 144 disk volume group? Could it cause > a problem, for example fragmentation? > Or do I use a divisor of 144, e.g. 72? > > > Best regards, > Samir Reddahi > > System Engineer | Systeem MF, AS400, DBA Operations > T +32 9 235 61 09 | M +32 478 80 68 30 > [email protected] > <mailto:[email protected]<[email protected]> > > > > www.securex.be <http://www.securex.be/> > > > > > - Confidentiality Notice - > > This communication and the information it contains is intended (a) for the > person(s) or organization(s) > named above and for no other person or organization, and (b) may be > confidential, legally privileged and > protected by law. Unauthorized use, copying or disclosure of any of it may > be unlawful! If you receive > this communication in error, please notify us immediately, destroy any > copies and delete it from your > computer system. 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