|From:||"Greg 'groggy' Lehey" <grog@xxxxxxxxx>|
|Date:||Tue, 14 Sep 2004 10:00:16 +0930|
On Monday, 13 September 2004 at 8:45:30 -0700, Matthew Dillon wrote: > If you want *real* RAID, you want to use an external raid with a SCSI > port. Second choice would be to use a real raid controller. Third > choice would be to use a software solution. Well, they're all *real* RAID :-) But yes, putting it in a BSD kernel is a bit of a hack. Volume management is a different issue. > Vinum is a rather fragile piece of software, it would not be my > first choice despite all the fine work done on it. The run-time components of Vinum are surprisingly (to me, anyway) robust. It's the configuration stuff that needs replacement, as mentioned in a previous message. > As far as Geom goes... well, I really dislike the idea of having > to implement complex drivers in the kernel. I have been slowly > cleaning up our IO infrastructure to allow IO devices to be > properly stacked (our disk layer, for example, is now properly > stacked), but ultimately I think the real win here will be to > form a streaming protocol that could run over a TCP socket to > govern the I/O (not necessarily NAS). Then one would be able to > build drivers to run in userland and/or on remote machines. The > only real latency issue is, as always, with READ ops, but a > kernel supported data block cache at the block device level > would mostly solve that issue. FWIW, I'm currently planning to write a userland callout for the file system so that I can prototype file systems in userland. If anybody's interested in following up on this one, please contact me. It obviously doesn't belong on this thread. Greg -- Finger grog@xxxxxxxxx for PGP public key. See complete headers for address and phone numbers.
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