Autopath question

[Edward Bender]

I am planning the config of an hpux server with 4 fibre connections thru two switches connected to an xp10000. The server will be running autopath to load balance the io across all 4 ports. If I were to zone and run a tape drive on 1 of the ports would autopath detect this io load and shift the disk io to the remaining 3 fiber ports? In other words, is autopath looking at the fiber card port load or some other disk only io value to determine how busy the port is? Thanks.

[Alzhy]

Edward, you'll be actually be better off with just using VxVM and DMP with your quad-pathed LUNs from an XP1000.

Moreover, I think you will get better performance if you do not quad path but simply dual path each LDEV/LUN.. if you've 100 LDEVs and 4 FC's, present 50 to the 1st pair and the other 50 to the other pair -- always making sure your storage VOLS/LVOLS are made up of LUNS from each component LDEVs spread out from each pair.

As far as AutoPath or any Multipathing/Load balancing detecting your Tape/Backup load on one FC path -- it will not detect it per se but AutoPath/DMP will try to use whatever balancing policy you've set it to.

BTW, it is still not a good idea to mix Disk and Tape LUNs on the same HBA/zone... It is still best for Tape LUNS to be on their own FC-HBAs and zone.

[Edward Bender]

So, if I use the policy "Least Bandwidth", will autopath detect the traffic from the tape and use the other ports more? I know it is better not to mix tape/disk but I may have to until I can afford to purchase additional hba's and switch ports. Is 4, 4gig ports, overkill for an hpux server running a 1gig database? Would I be better off just using 2 ports for disk and 1 for tape instead of combining disk/tape on one of the four?

[Alzhy]

Wow, if you're using 4Gbps HBAs and also 4Gbps Switch ports, I really do not think you need 4 of them -- specially for just a 1GB Database...

[Edward Bender]

Sorry, I ment a 1 Terabyte Database (SAP/Oracle)

[Alzhy]

And yes on the less bandwidth policy question.

BTW, are all your XP10000 Front Ends also 4Gbps provisioned?

[Alzhy · Accepted solution]

Yes 4x4GBps would be considered standard these days for TB sized DB instances -- but it really all depends on your database... the best is ovserve per HBA IOPS/BPS rates if you're hitting limits already ...

[Edward Bender]

Yes, all of the XP10k front ends are 4gig. Our engineer is using only 8 of them. 4 are to be used for SAP data and the other 4 are for email and other windows server data.