IMHO .. vxVM beats SDS hands down.. SDS has one main advantage, its free whereas the license for vxvm just ain't cheap (although I believe its shipped free by Sun with certain arrays)
SDS is primary useful in a small disk environment where the cost of a Veritas licence would be pointless..However if your managing loads of disk SDS can become an administrative nightmare..
In a large environement the main disadvantage is that SDS is limited to 7 partitions per disk, so if you're intending to do a lot of striping you can very soon find yourself running out of partitions. vxVm on the other hand handles something like 10,000 partitions per disk meaning you can always optimise for performance..
I'm sure I could ramble on for ages but basically vxVM is far more powerful and flexiable tool. If you've got it use it.
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