Re: Re: Re: PostgreSQL over NFS?

* tc lewis <tcl(at)bunzy(dot)net> [010209 17:08] wrote:
>
> > >
> > > how's that? storage arrays will require you to use a filesystem that your
> > > operating system supports. or do some storage array companies provide
> > > their own filesystems and drivers for misc systems? same thing i guess.
> >
> > It has a persistant write cache, meaning it can ACK a write as being
> > sync'd to disk even if it's only been copied into the RAID's memory
> > cache (because it's persistant). Same thing that netapp does.
> >
>
> hmm, i suppose. i guess the filesystem wouldn't need to understand the
> logic of the underlying device. not sure. i don't think i've ever been
> presented with a storage array that does what you're saying (not saying
> they don't exist).

All it does is present itself as a disk that super fast at writing
as long as the cache doesn't fill up. I have an older card:

amr0: <AMI MegaRAID> port 0x1080-0x10ff irq 18 at device 11.0 on pci0
amr0: firmware UF80 bios 1.61 128MB memory

That has a slot for battery backup of the RAID cache. If the
machine was to reboot, the raid would sync the cached data to
disk sometime after coming back up.

--
-Alfred Perlstein - [bright(at)wintelcom(dot)net|alfred(at)freebsd(dot)org]
"I have the heart of a child; I keep it in a jar on my desk."