SAN vs Internal Disks

[Pedro Cirne]

Hi,

I have rp7420 with 2 mirrored 73.4Gb internal disks.

This box is also connected to a SAN with 2 HBA.

I have 30Gb filesystem on internal disks with high I/O, would it be more efficient to move it to the SAN?

I think the answer is yes, but I would like to have other opinions on advantages/disadvantages on this.

Thank you,

Pedro

[A. Clay Stephenson · Accepted solution]

I suspect what really happened was that with 73GiB internal disks, you just couldn't let all that space go unused so you put applications and/or data into vg00. Vg00 should really be used for the OS and directly OS-related applications and nothing else. If all the extra unused disk bothers you then set up a separate dump area and do not mix the swap and dump areas.

You SAN should be used for all other applications and this will leave vg00 relatively quiescent. If you are seeing lots of activity in /var, it is probably a result of /var/tmp and possibly /var/spool/lp. You might consider setting these up as separate file systems under another VG as well.

I really prefer that my boot disks be directly attached just so there is no finger-pointing when something fails.

[James R. Ferguson]

Hi Pedro:

> I have 30Gb filesystem on internal disks with high I/O, would it be more efficient to move it to the SAN?

I presume that the filesystem in question is *not* within a standard vg00 logical volue. Given that, yes, move it out/off of vg00.

Your vg00 should be mirrored and devoid of anything but the standard logical volumes for HP-UX. This makes cloning, upgrades and/or cold-installations much, much easier.

Besides, you can often get performance benefits from SAN-based filesystems.

Regards!

...JRF...

[Pete Randall]

You don't mention what type of SAN it is nor how it's connected, but, as a general rule, SANs are designed with performance in mind. They're faster, more efficient and highly available - much more so than internal disks. I would say yes, the SAN is going to be your better choice.


Pete

[Pedro Cirne]

Hi,

Thank you all, I completely agree with all of you :-)

Pedro