/var/adm/crash and partitioning during install

[Adam Garsha]

We have 32GB of physical memory and the system install CD wants us to allocate 32+ GB's of our 72GB drives to support crash dumps.

Questions:
1.) Is it supported to mount a SAN drive to /var/adm/crash to collect potential dumps?

2.) If so, will the system still boot if the SAN isn't available (and /var/adm/crash cannot be mounted)?

Do I need to allocate 16GB to swap+dump also??? I should never be swapping and only have minimal paging.

I want to do this (any issues):

/stand -> 1
/ --> 4
/home --> 8
/usr --> 12
/var --> 12
/opt --> 12
swap+dump -> 16
/tmp --> 2

And mount SAN disk to /var/adm/crash maybe? Tell me I'm crazy, if it is so. What would you do?

[Mel Burslan · Accepted solution]

only down side of /var/adm/crash being on SAN that I can see is, if your SAN attachment channel, let it be SCSI or fiberoptic, induces a panic, you may not be able to get a dump to analyze.

As far as the size of the crash area goes, quarter of the size of physical memory should be enough to capture what will help you to analyze the crash. After all you are only interested in the OS area in memory when a crash happens 99.9% of the time. Also consider that the dump, when it is written to the disk, is compressed quite a bit. So 1/4th of actual physical memory is quite generous allocation in my opinion on today's large memory systems.