Re: IDE ATA RAID under Linux
hi ya jen
On Wed, 7 May 2003, jennyw wrote:
> On Tue, May 06, 2003 at 11:47:09PM -0700, Alvin Oga wrote:
>
> > if you want ot do hot swapping, do lots of testing to confirm that
> > your reading and writing can in fact survice a disk hot swap w/o hiccuping
> > and burping
>
> Does this mean that you think that existing hardware RAID hot swap
> technology is a bit lacking?
hot swapping ... depends ..
- if scsi based disks ... i'd be mroe confident it'd work properly
-- test == pull the disk out while its writing a 1GB file and
see if it recovers properly when its re-inserted
> > for mirroring ( on 2 disks )... use software raid1
>
> Is this because of cost?
yes ... i dont see any value to a 2 drive mirrored system if its
suppose to prevent data loss ...
- it might extend your uptime after your dirve dies, but
will NOT protect against data loss, when your 2nd disk disks
too for whatever reason
-- all dead disks needs to be replaced asap .. and until that is done,
your raid is offline, unless you have idle hot-swap disks can be
readily turn on to "live mode" from hot spare
> > raid will NOT protect you if the disk drive died due to
> > bad power, bad memory, rogue cpu, etc..etc..
> > - you learn the hard way ... ( we had bad memory, that kept
> > "fixing" the disks with its bad memory content )
>
> All too true ... I'll be backing up nightly, but want the RAID for the <
> 1 day situations.
nightly backups done properly, from the last full backups is a good
thing to do .. where each backup is kept on a different disk/system
> > > The Arco IDE solution looks good too because to the OS an array will
> > > appear as a normal IDE disk. Any thoughts on that?
> >
> > that holds true for 3ware too
>
> Really? I didn't know that. That's good to know.
meant that 3ware treats(converts) ide disks like a scsi drive as far as
the system is concerned ... a good thing ... in general
- cold swap or hot swap is a different problem
c ya
alvin
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