ORacle on SAN ( XP 512 ) and OFA ???

[Henrique Silva_3]

I am looking at such solution for our new implementation, and have a question about SANs in general.

On a local system, you try to balance the load buy getting multiple controllers, disks, spindles, etc. With SANS, how is that done ? Does the SAN ( XP 512 ), have many controllers as well ? Should we have many NIC cards here to access the SAN ? say on a dedicated GBit network setup I would have 3 or 4 NIC cards coming off my superdome to the SAN ? I worked with EMC SANs before, but not with HPs !!!!

Thanks,

Henrique Silva

[Roger Baptiste · Accepted solution]

Hi,

From a SAN point of view, XP and EMC or any other disk array for that matter is the same. We don't have to deal with LAN port here. Take a simple case of two servers connected to a XP512.

XP512 has Fibre cards (also known as CHIP ports in XP-speak) which are used to connect to the Servers. You can connect the XP directly to the servers or you can connect through a Switch. If the XP frame is being used by lot of systems, then a switch is preferable.

For better performance, you can make more XP fibre ports visible to the system. Say, you have four Fibre cards on the System, you could connect all the four cards to four different ports of XP. That way you have four connections which can be load balanced in pairs of two (primary and alternate PVs).

This is only part of the configuration. There are other things to consider with the layout of disks in the Xp, the number of ACPS (disk controllers) you want to lay them on, the LUN configuration, spreading the database files etc.

HTh
raj

[harry d brown jr]

Henrique,

The same logic that applied to EMC's SAN applies to anyone's SAN, unless of course M$ came out with one - inwhich you would quadruple everything :-)

Bandwidth and bottlenecks should be monitored at all times, and if necessary, more switches, FC cards, HBA's should be deployed.

live free or die
harry

[Wodisch]

Hello Henrique,

on a RAID-box (like XPs and EMCs) I would rather go for "SAME" - stripe and mirror everything, since the *real* disks in there are too big to be allocated for only, say, on-line redo-logfiles, but are split into "LUNs"...

There is a nice whitepaper about this (SAME) available on the Oracle-Technet!

HTH,
Wodisch

[Henrique Silva_3]

That is what I thought.

Thanks, I will look for the SAME white paper and start reading more about the XPs.

Henrique Silva

[Roger Baptiste]

hi,

Regarding XPs: You have the choice of RAID5 or RAID 0/1 . The general leaning is towards RAID5 on the XP arrays. Another things is the Size of LUNS you want to choose. Optimal one would be Open-E which is around 14Gb lun size (you can use smaller ones or much larger ones that 14gb) Once you decide this, then work on picking LUNS for creating the VGs. This will be based on your VG layout strategy, how many ACPs(disk controllers at XP level) you want to spread them out on, the stripe size etc.

Another important thing to note is the CHIP ports (fibre ports as seen from the system end) have two processors, one for odd luns and another for even luns. So make sure you use both even and odd numbered Luns on a fibre path. For eg: if you use luns 00, 01,02 and 03 for a VG on two Fibre paths 5/1 and 9/1 . Make sure, luns 00 and lun 01 are primary on 5/1 and luns 02 and 03 are primary on 9/1. That way you make use of both processors of a fibre port. This is a XP pecularity , not there on EMC.

HTH
raj