Originally posted by: steevojb

Hi there,

Are there any special requirements for allocating paging space on the SAN. We have a p570 connected to a ds6800. I assigned a LUN for paging last week, when the system was rebooted over the weekend the LUN wasn't available.

TIA

Steve
#AIX-Forum

Originally posted by: SystemAdmin

To my knowledge, even though you could put paging on the SAN, it isn't recommended. If your connections reset or get lost for any reason, chances are the server will lock up. It is best to keep the paging on local drives and if you have more than one paging space, to keep them in equal numbers and the same size. For example...you can do 1/8gig, 2/4gig, or 4/2gig paging spaces, depends on what you have for resources and then how much memory is in the server. I usually use 2 paging spaces on local drives and then utilize the drives for something not very io intensive.
#AIX-Forum

Originally posted by: VirtualGreg

I have several customers that boot from the SAN and hence have their paging space on the SAN. Managing enterprise disk is a little easier than managing LVM mirroring. RAID storage makes life a bit easier and less error prone (e.g., forgetting to re-mirror your paging space if you replace a disk).

BTW, if you have a lot of I/O going to your paging space(s), you should have more memory.

The problem I have with internal disk (other than management) is the wasted space. After you load AIX - what do you do with the spare 70GB? :-)
#AIX-Forum

Originally posted by: cd3lgado

Hi

I have seen this kind of config before. In fact if you use VIOS with SAN based LUNs to create vscsi server adapters then paging space will be in SAN. Only concern is to avoid at all cost high I/O paging (thrashing) cause this behavior consumes CPU cycles in the SAN processors as well as SAN cache memory wasted. Not to say that a huge writting pattern can take a RAID5 device to a performance problem. in AIX you can use the VMM (vmo -a) options to control paging. Linux systems does not have this kind of advanced tuning options.

Hope this helps.
#AIX-Forum