Note that you can also put many IDE controllers in one machine and RAID
On Sun, 21 Mar 1999, Glenn.McGrath wrote:
> Hi people, disclamer first, im new to this list and have a lot to learn
> on kernels and distributed filsystems(DFS).
> The way i see it network technology is developing at a much faster rate
> than local media, currently. (bleeding edge technolgy) gigabit ethernet
> (120MB/s), is faster than ulta-wide-scsi2 (80MB/s max), so getting data
> simultaneously from a dozen servers (ide drives or whatever) on a
> switched Gbit network is fastest way to get data into your comp.
> Comparisons can be made with different technology, but im sure you get
> the point.
> I realise that linux already has distributed filesystem support, with
> coda (xFS on the horizon too), but i thought this may be a different
> approach, that could have some advantages over other DFS's, i thought
> it to be worthy of discussion anyway, so let me know if im wrong.
> By combining two existing features, network filesystem*(eg NFS, SMB?),
> and RAID , it should be possible to setup a raid system over a network
> instead of over /dev/hdxx or /dev/sxx (whatever scsi is) with minimal
> effort as compared to doing a DFS from scratch, or without kernel level
> support . The advantages i see in this method are.
> 1) NFS and RAID already exist, its always good to re-use existing time
> proven code.
> 2) NFS is filesystem independent, i.e. you could setup NFS to work on a
> ext2, fat32 or any linux supported filesystem, so each node of
> distributed filesystem could be a different filesystem type.
> 3) Because it exists(partly?) in the kernel it gains some magical
> performanc increase (well, i dunno myself, but thats how legend has it,
> although from what ive seen great debate goes into what belongs in
> kernel/user space)
> 1) Latency would be a problem for small files, the common method used by
> most filesystems is to group files into chunks and send the whole lot,
> of course small files could be stored/cached locally.
> 2) I would think raid 2/3 would have been handy, this doesnt currently
> exist with linux's raid implementation because the reliability of local
> drives isnt really questionable. But raid 4/5 would be the fastest.
> Im sure there ae some problems im overlooking, it would take a while to
> nut out the fine details of how it should work, e.g. coordinating what
> operations should/shouldnt proceed reguarding permissions and security
> etc. But maybe this has even been tried before and im not aware of it.
> * I distinguish a network filesystem to be the client/server model,
> whereas a distributed filesytem has multiple clients/multiple servers
> Glenn McGrath
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