Is it necessary to mirror Swap Slice?

[gallows]

I just noticed on one of my Solaris 9, 280R servers that
Slice 1, (swap) is mirrored but is not in vfstab. The 280 has 2gb memory but is running an Oracle DB which has me a little concerned.

1. Is it necessary to mirror swap partition when mirroring root disk?

The df -lk shows swap as:

swap 2928880 24 2928856 1% /var/run

The mirror is d31 and shows up with metastat but nowhere else.
The swap -s shows that swap space is being used. Do I have anything to worry about?

Thanks
gallows

 

[mrn]

Yes.

If you want fault tolerance, you should mirror your swap device. There is no point in mirroring your system if you do not also mirror swap.

Mike

Unix *is* user friendly. It's just selective about who its friends are.

 

[gallows]

Thanks Mike.
I found it in the vfstab, but it is set to NO to mount at boot time. I can see where it is being used so I guess I am ok.

gallows

 

[Annihilannic]

It is set to 'no' because you can't 'mount' a swap partition as it does not contain a filesystem.

The one you are seeing in df -lk is a "tmpfs", which somewhat confusingly are stored in swap. The /tmp filesystem is often like this as well. Because they are only for temporary files they are held in memory first, and if the system is short of memory then they are written to swap. Any files on a tmpfs are lost when the system is rebooted.

Annihilannic.