Jarod Wilson <[EMAIL PROTECTED]> says: > Something odd going on there, I have an almost identical setup for > my master backend, and NFS works great at handling multiple HDTV > streams (both my HD capture devices are in slave backends that write > to the master via NFS), along with the occasional SD stream thrown > in as well.
To make a long story short, my 2.8TB JFS-on-LVM2-on-software RAID 5 array has certain mysterious performance bottlenecks that result in 7.5-10MB/s local write speeds, despite eight spindles and two 3Ware 7506 controller cards in JBOD mode and on separate buses and with iowait never going above a few percentage points at the very most. Over the network that's even slower, of course. I've going to be rebuilding the array after backing it up to an Infrant 600 (the clear winner, in my mind, among the recent spate of "NAS in a shoebox" offerings popping up all over the place) with four 500GB drives I'll be temporarily using in RAID 0 for the time being, and am looking forward to finding out whether the bottleneck is in mdadm, lvm2 (the likeliest suspect in my mind; none of the several academic self-assembled terabyte-RAID 5 array setups I've read benchmarks for online seems to use it, although otherwise essentially identical), JFS, or elsewhere. I would be surprised if, once I reach write performance on the array closer to theoretical potential, I can use NFS to stream recordings to it without any trouble. But in the meanwhile I'm glad Samba lets me stream a HDTV recording while also playing back a HDTV stream with no IOBOUND error messages (except the very occasional one or two if I'm doing something disk- but non-MythTV related on the frontend/backend MythTV box); after a month of butting my head against seemingly-endless IOBOUND messages with NFS v3 that's a good thing, believe me. -- Yeechang Lee <[EMAIL PROTECTED]> | +1 650 776 7763 | San Francisco CA US
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