First, thanks to everyone for the helpful responses. On Fri, Mar 12, 2010 at 3:36 AM, Kristleifur Daðason <kristleifur@xxxxxxxxx> wrote: > > I agree with others on the list - I believe that LVM will perform well > as a flexible stripe wrangler on top of mdadm arrays. For instance > some LVM striping over mdadm parity-based stuff underneath. I made a typo in my original post, so let me clarify. In my configuration, I have a pair of dual-channel FC HBA cards. I currently have three hardware RAID-5 chassis connected to three of the HBA channels, and I am using Linux md to perform RAID-0 striping across the channels. This gives me very high performance -- 800 MiB/sec sustained reads and writes, for hundreds of gigabytes, using XFS -- at very modest CPU utiliziation. What I want is to connect a fourth, identical hardware RAID chassis to the fourth HBA channel and then re-stripe the md RAID-0 across all four units. I now understand that this is not currently supported. > Do you want to add a whole new stripe device, so changing the > coarse-scale layout, or grow the underlying data containers? New stripe device. > As you are running striped, I assume that the data is either > perishable or backed up. My data is all reproducible. (The system spends its time processing large volumes of data that originated somewhere else.) We are using underlying RAID-5 chassis to improve MTBF, not to prevent data loss. > I'd suggest you look into moving to LVM. Thanks to Michael Evans and to you for this suggestion; I will investigate LVM. Thanks once again to everyone who responded. The world of Linux RAID may be "gas-lit and magical", but in many ways the support is superior to any commercial product I have seen. - Pat -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
