Mike Gerdts wrote:
On 11/7/06, Richard Elling - PAE <[EMAIL PROTECTED]> wrote:
> d10 mirror of c0t2d0s0 and c0t3d0s0 swap (2+2GB, to match above)
Also a waste, use a swap file. Add a dumpdev if you care about
kernel dumps, no need to mirror a dumpdev.
How do you figure that allocating space to a swap file is less of a
waste than adding space to a swap device?
If you ever guess wrong (which you will), you can just make another
swap file or redo the existing swap file. If you carve out a slice,
then reclaiming the space is much more difficult. Creating more slices
tends to also be difficult, so when you quess wrong you may still end
up swapping to files.
Simple /. Make it big enough to be useful. Keep its changes to a
minimum. Make more than one, so that you can use LiveUpgrade.
For consistency, you could make each disk look the same.
s0 / 10G
s6 zpool free
s7 metadb 100M
Since ZFS can get performance boosts from enabling the disk write
cache if it has the whole disk, you may want to consider something
more like the following for two of the disks (assumes mirroring rather
than raidz in the zpool):
s0 / 10G
s1 swap <pick your size>
s3 alt / 10G
s6 zpool free
s7 metadb 100M
The other pair of disks are given entirely to the zpool.
Use two disks for your BE, the other two for your ABE (assuming all are
bootable).
In any case, be sure that your root slices do not start at cylinder 0
(hmmm... maybe this is SPARC-specific advice...).
I think this is folklore. Can you cite a reference?
NB. traditionally, block 0 contains the vtoc and for SPARC systems,
blocks 1-15 contain the bootblocks, see installboot(1M).
Cylinder 0 may contain thousands of blocks for modern disks. It is
a waste not to use them. AFAIK, all Sun software which deals with
raw devices is aware of this.
One way to populate
an ABE is to mirror slices. However, you cannot mirror between a
device that starts at cylinder 0 and one that does not.
Where is this restriction documented? It doesn't make sense to me.
Maybe you have a scar from running Sybase in a previous life? ;-)
-- richard
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