On Mon, January 25, 2010 14:11, Simon Breden wrote: >> I've given some though to booting from a thumb drive >> instead of disks. >> That would free up two SATA ports AND two hot-swap >> disk bays, which would >> be nice. And by simply keeping an image of the thumb >> drive contents, I >> could replace it very quickly if something died in >> it, so I could live >> without automatic failover redundancy in the boot >> disks. Obviously thumb >> drives are slow, but other than boot time, it should >> slow down anything >> important too much (especially if I increase memory). > > I've seen anecdotal evidence for not using thumb drives, speed, > error-prone, logging etc, but maybe someone else can provide some more > info. If you have a 5.25" or 3.5" slot outside of your 8-drive drive cage, > you could use two 2.5" HDs as a boot mirror, leaving all 8 bays free for > drives for future expansion needs, as a possibility. But if six data > drives are enough then this becomes less interesting. An possible option > though. I chucked 2 SSDs into one 5.25" slot for my boot mirror, which > worked out nicely, and a cheaper option is to use 2.5" HDs instead -- with > a twin mounter here: > http://breden.org.uk/2009/08/29/home-fileserver-mirrored-ssd-zfs-root-boot/
I've got at least one available 5.25" bay. I hadn't considered 2.5" HDs; that's a tempting way to get the physical space I need. I'm running an SSD boot disk in my desktop box and so far I'm very disappointed (about half a generation too early, is my analysis). And I don't need the theoretical performance for this boot disk. I don't see the expense as buying me anything, and they're still pretty darned expensive. I've considered having the boot disks not hot-swap. I could live with that, although getting into the case is a pain (it lives on a shelf over my desk, so I either work on it in place or else I disconnect and reconnect all the external cabling; either way is ugly). Logging to flash-drives is slow, yes, and will wear them out, yes. But if a $40 drive lasts two years, I'm very happy. And the demise is write-based in this scenario, not random failure, so it should be fairly predictable. >> But does anybody have a good 2-port card to recommend >> that's significantly >> cheaper? If there is none, then future flexibility >> does start to look >> interesting. > > Maybe others can recommend a 2 or 4 port card. When I looked mid-2009 I > found some card but I didn't really feel like the hardware or possibly the > driver was that robust, and I prefer not to lose my data or get more grey > hairs/headaches... so I chose the 8-port known robust card/driver option > :) And you just know that you'll need that extra port or two one day... I'm trying to simplify here! But yeah, if nobody comes along with a significantly cheaper robust card of fewer ports, I'll probably do the same. > Indeed, mirrors have a lot of interesting properties. But if you're > upgrading now, you might want to consider using 3 way mirrors instead of 2 > as this gives extra protection. 6 or 8 hot-swap bays and enough controllers gives me relatively few interesting choices. 6: 2 three-way, or three two-way; 8: four two-way, or...still only 2 three-way. I don't think double redundancy is worth much to me in this case (daily backups to two or more external media sets, and hot-swap so I don't wait to replace a bad drive). Actually, if I move the boot disks somewhere and have 8 hot-swap bays for data, I might well go with three two-way mirrors plus two hot spares. Or at least one. -- David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
