Hi Darren,
I do have a disk array that is providing striped LUNs to my Solaris box. Hence I'd like to simply concat those LUNs without adding another layer of striping.Is this possibile with ZFS? As far as I understood, if I use zpool create myPool lun-1 lun-2 ... lun-nI will get a RAID0 striping where each data block is split across all "n" LUNs.Individual ZFS blocks don't span a vdev (lun in your case) they are on one disk or another. ZFS will stripe blocks across all available top level vdevs, and as additional top level vdevs are added it will attempt to rebalance as new writes come in.
That's exactly what I would like to avoid.I do have several Solaris servers, each one mounting several LUNs provided by the same
disk-array.The disk-array is configured to provide RAID5 (7+1) protection so each LUN is striped
across several physical disks.If I was mounting multiple LUNs on the same Solaris box and ZFS was using them in RAID0 then the result is that each filesystem write would span across a *huge* number
of physical disks on the disk-array.This would almost certainly impacting other LUNs mounted on different servers.
As the striping is already provided at hardware level by the disk-array, I would like to
avoid to further stripe already striped devices (ie LUNs).
If that's correct, is there a way to avoid that and get ZFS to write sequentially on the LUNs that are part of myPool?Why do you want to do that ? What do you actually think it gives you, other than possibly *worse* performance ?
ditto.Of course the alternative is to get the disk-array providing non-striped LUNs but I suspect that hardware striping is way more efficient than software strping, no matter of good ZFS is.
Cheers, Piero
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