Re: Moving / from one disk to another

On Fri, 14 Mar 1997 19:37:30 -0500, Lou Avrami <L.Avrami_at_dialogic.com> wrote:

>Hello all,
>
> We're upgrading our production server from a Sun Sparc 1000E with a
>SPARCstorage Array Model 100 disk storage system to a Sun Ultra 4000
>with a Model 200 disk array unit (it's a big, refrigerator-sized
>cabinet). The 200 storage unit comes with 4.2 gig disks, while the 100
>has 2 gig disks. The production server hosts several Oracle databases.
>
> As part of our upgrade, we will be detaching the 100 SPARCstorage
>unit from the 1000E, and hooking it up to the 4000.
>
> We're trying to figure out what file systems to put on which disks.
>To us, it would seem to be a waste of space to put / (the root drive) on
>one of the 4.2 gig disks. If we did so, and wanted to try to limit I/O
>as much as possible, we should not put anything else on that disk. What
>we'd like to do is put / on one of the 2 gig disks from the 100 Array,
>and put Oracle datafiles on the 200 Array with the 4.2 gig drives. But
>the 2 gig disks will not be available to the 4000 until we unplug them
>from the 1000E, and we can't do that ahead of time, since that houses
>our production databases.
>

....

> Some related questions: From and I/O perspective, is it better to
>have /usr on the same disk as /, or should they be on separate disks?

Well since most of the data in /usr is read-only it really shouldn't matter if they were together or not since it will probably end up in the filesystem buffer cache anyway. I believe the Adrian book even recommends using one partition for the OS (one big /). However, be aware of a limitation I found in Solaris that the boot partition / cannot be any bigger than 1.0GB or the loader goes nuts.

> Should /tmp be on the same disk as /, or on a separate disk? Should
>/tmp and /usr share a disk?

I usually put /tmp on swap. Any reason why you don;t what to do this? It's the Solaris default.

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