Hehe. One external, 8-bay enclosure, using two SATA ports. The ports go directly to the motherboard - no additional controller. Server software is Ubuntu 12.10, with ZFS added on from the zfs-native PPA. When I was using this as md-software RAID5, I had two disks in each half of the enclosure. No performance issues. Now this is 8 disks rather than 4, and raidz2 (so RAID6) rather than RAID5, but still... hit play on a video and wait 6 seconds for it to start?... that's a bit... off. No errors except the three checksum errors I've had. On Mon, 11 Nov 2013, Thomas Lunde wrote: > > All of the drives are in a single external enclosure? > > How is that enclosure connected to the rest of the PC? USB? (2? 3?) eSATA? FireWire? Something else? > > If eSATA, then you may be having issues with a port multiplier. > > In any case, it's really hard to troubleshoot by guessing. So, if you'd like further help to address performance issues, maybe you could provide a full hardware and software description of the system. :) > > Thomas > >> On Nov 11, 2013, at 9:09 PM, tclug at freakzilla.com wrote: >> >> No idea what most of what you said is, no (: >> >> These are all identical drives, in an external enclosure, so none of it is my own SATA cables. And again, no errors when they were in a software RAID5 (though there were half as many drives) and nothing in the system logs, which is why I am concerned... >> >>> On Mon, 11 Nov 2013, Thomas Lunde wrote: >>> >>> >>> Bit flips like this helped me to discover that two of my 10 SATA cables were marginal. >>> >>> Since these are >2T drives, did you do anything with ashift? Depending on which ZFS implementation you're using, this question might not make sense? >>> >>> An array of drives where some are faking 512 byte sectors and ( some are really using 512 byte sectors OR some are using 4K sectors ) can cause abysmal performance. >>> >>> Thomas >>> >>> _______________________________________________ >>> TCLUG Mailing List - Minneapolis/St. Paul, Minnesota >>> tclug-list at mn-linux.org >>> http://mailman.mn-linux.org/mailman/listinfo/tclug-list >> _______________________________________________ >> TCLUG Mailing List - Minneapolis/St. Paul, Minnesota >> tclug-list at mn-linux.org >> http://mailman.mn-linux.org/mailman/listinfo/tclug-list > _______________________________________________ > TCLUG Mailing List - Minneapolis/St. Paul, Minnesota > tclug-list at mn-linux.org > http://mailman.mn-linux.org/mailman/listinfo/tclug-list >