On Mon, January 25, 2010 15:26, Simon Breden wrote: >> 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. > > Yes, it is an interesting option. But remember about any necessary cooling > if moving them from a currently cooled area. As I used SSDs this turned > out to be irrelevant as they don't seem to get hot, but for mechanical > drives this is not the case.
Well, they'll be in a space designated as a drive bay, so it should have some airflow. I'll certainly check. >> 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. > > Which model/capacity are you using? > Yes, they are not quite there yet, and I certainly should probably not > have bothered buying these ones from the price perspective, as two 2.5" > drives would have been fine. But for a desktop machine I'm quite surprised > you're disappointed. But there is currently enormous variation in quality > due to firmware making huge differences. They can only improve :) It's an OCZ Core II, I believe. I've got an Intel -M waiting to replace it when I can find time (probably when I install Windows 7). >> I've considered having the boot disks not hot-swap. >> I could live with >> hat, 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). > > I think I would be tempted to maximise the available hot-swap bay space > for data drives -- but only if it's required. I'm currently running 400GB drives. So I could 5x my space just by upgrading to modern drives. I'm really not short on space! What's it cost to run a drive for a year again? Maybe I really should just replace one existing pool with larger drives and let it go at that, rather than running two more drives. The spare bays I have are exposed, so I can replace my two boot drives with 2.5" drives in hot-swap bays. There are some 4x2.5" hot-swap in 5.25" bay products out there, not even that expensive. Then I'd have 12 drives available, and if I get the 8-port controller, 14 controller ports. I can use the 8 3.5" bays for data disks (alternating the two controllers), use two of the 2.5" bays for boot disks (again alternating controllers), and have two slots left for hypothetical future SSD L2ARC or something :-). The 6 ports on the motherboard run exactly half of the 12 bays, 6 of the ports on the add-in-card run the other half of the 12 bays, and 2 ports on the add-in card go to waste, so every mirror pair can be split across controllers. >> 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. > > Not an expert on this but I seem to remember that constant log-writing > wore out these thumbdrives out, but don't quote me on that. 2.5" drives > are very cheap too, and would be my personal choice in this case. 2.5" drives seem to bottom out at $50 (I've seen $45, nothing lower). And the smallest I can find are 2x the size I need :-). > One example, if one has a large case, is to make a backup pool from old > drives within the same case. I haven't done this, but it has crossed my > mind. As all the drives are local, the backup speed should be terrific, as > there's no network involved... and if the drives were on a second PSU, > which is only switched on to perform backups, no electricity needs to be > wasted. I have to look into whether this is a workable idea though... The case is huge, but most of the space is already taken up with the two sets of 4 hot-swap bays. Wouldn't be putting my backup pool internally anyway, though. The important thing about the backup pool is that it gets taken off-site regularly. I'll probably add a third backup drive, and a bigger one. (Single-file recovery is from snapshots on the main data pool, rather than from backups.) Also harder to grab the whole case and run with it in event of fire, or put it in a local fire safe, etc. >> 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). > > Indeed, and often forgotten by home builders, is that if you have > dependable regular backups which employ redundancy in the backup pool, > then you don't need to be so paranoid about your main storage pool, > although I personally prefer to have double parity. Extra insurance is a > good thing :) I use single-disk backup pools; it's just so much more convenient (currently WD 1GB USB drives; remember my data pool is only 800GB. And it looks like drive size will increase fast enough for me to stay with single-drive backup pools for a while :-). -- 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
