2009/4/14 Miles Nordin <car...@ivy.net> > > well that's not what I meant though. The battery RAM cache's behavior > can't be determined by RTFS whether you use ZFS or not, and the > behavior matters to both ZFS users and non ZFS users. The advantage I > saw to ZFS slogs, is that you can inspect the source (and blogs about > the source) to determine lots of details about how slogs behave > including answers to the questions above. Better yet, with some skill > you can change the answers to suit yourself. This process leads to > some mix of good behavior and well-understood errata, while the other > process leads to frustration, war stories, and cargo-cult maintenance > ``procedures''. >
This is a good point. Performance vs reliability is the constant struggle, but if you don't have the right information you just have to go with what you know. >> it's so extremely cheap > > nl> That;s the big point. 10,000 USD for a 2U 12 disk 10TB raw > nl> NAS or 100,000 USD for the equalivent appliance. > > here I was talking again about battery-RAM RAID-on-a-card vs. slog. > The battery-RAM is maybe a little bit less extra cost than X25E or > ACARD, like $250 instead of $500, plus it doesn't consume a drive > slot. This amount of cost edge matters to people with large clusters, > or to the rented-hardware hosting business. Problem is the ACARD units while maybe being cheap are not useful - 5.25" form factor is no good in any rack based storage system. > > If both firmware and driver for the LSI 1078 cards were open source, I > bet we could turn the RAM on the LSI cards into a slog. This would be > better than a SATA slog because it'd have full PCIe bandwidth and > low-latency to the RAM instead of just SATA. but it's all > proprietary, so I'm going with the slog. and keeping an eye on > FreeBSD, since maybe if they manage to get ZFS working well in 8.0 I > can finally get ZFS on top of proper drivers for the disk controller > card and SCSI mid-layer. > As you say, without detail a good slog is really the only option. Does anyone know if the Fusion-io cards have solaris drivers yet? Nicholas
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