Re: zootle Peter Campbell asdf mousepads...
I'm not saying ZFS can't work with hardware RAID, it is quite happy to work with it. I've built a number of systems with RAID controllers that can't do JBOD (the Dell PERC 710 in particular). The virtual devices just appear to the OS as drives. What I am saying is it an inconvenience for the system builder (extra $, time wasted stetting up virtual volumes) and administrator (one more tool to use to manage disks). It can be more of an inconvenience when the RAID hides errors from ZFS which prevents the OS from recognising a failing drive. This has happened to me twice with Dell systems. The resource load on the system CPU is negligible. As for RAM, I'm sure you pay a lot less for system memory than your RAID vendor charges for cache memory.
I suggest JBOD because it is a cleaner, lower cost solution. It lets ZFS (and the host OS) directly manage the drives without an unnecessary intermediate layer getting in the way.
ZFS is tried and tested. It has been used for all of Sun, now Oracle's storage products for many years. The battery backed cache saves nothing. All my production systems have power protected log devices, so I can pull the system power until I get RSI before loosing data. I have tried and I got very bored.... The drive write cache is only a problem when the drive lies about honouring sync writes.
Biting the hand that feeds IT
