I don’t know the specific cards, I was just saying that if the card
supports hot-swapping drives, you can do it regardless of whether you are using
a RAID1 array or a RAID5 array. -----Original Message----- With
which adaptec card for scsi ? Is
there any way to do it with ide drives and adaptec 1200 for exemple ? -----Message d'origine----- Ben is right.
You can do the same thing with a hot-swappable RAID1 array. Just unplug the bad one and plug in the
new one (the way I understand it anyway, haven’t had a failure on one yet) and it
rebuilds, all online. -----Original
Message----- If a RAID 1 set has a failed
disk , you HAVE to break the mirror and recreate the mirror with the new disk. This means Server
downtime. If a RAID 5 set has a
failed disk, you simply replace the disk (especially hot pluggable) and the
server STAYS RUNNING.. NO downtime on the server. RAID 5 was
designed for this. It does not give you the same downtime when you have to
down the server, replace the disk and recreate the mirror.. RAID 5 will know
you replaced the failed disk and rebuild it on the fly. The server may see some
performance degredation, but it will stay running..and you dont need to down
the server at all. Replaying the log files
most certainly does come into play when you create a new DB.. Ive gone thru
this with PSS! -----Original Message----- How does
a RAID 1 (mirroring) not keep you running in the event of a failure? I'm
curious. It most certainly IS fault-tolerant. If you lose a disk
from RAID 1, you are still running. You don't HAVE to run maintenance
until you decide to. Now, certainly, it would be idiotic NOT to replace
the failed disk right away and break/re-create the mirror, but with newer RAID
controllers, you can even do this online. RAID 5 will give you the EXACT
same downtime. You replace the dead drive, and you wait while your RAID
controller rebuilds the stripe set. But again, what is the difference
between the 2 in terms of time? What, a couple of minutes? I do
concede that AS LONG as your databases and log files are kept on separate
spindles, then I personally don't care whether you use RAID 1 or 5.
Replaying the log files comes into play when you restore the database from tape
backup. I don't think it applies to creating a new database.
Circular logging IS on by default, but most Exchange admins with experience
(meaning those that know about Exchange and its features and why certain
features are used and why others aren't) turn that feature off as one of the
first steps once they build a server. Ben
Winzenz, MCSE Network/Systems
Administrator Peregrine
Systems List Charter
and FAQ at: List Charter
and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm |
Title: Message
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