RE: Why would anyone install Exchange on a PDC?

[Allen Crawford]

Title: Message

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----- From: MHR(Michael Ross) [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 12:42 PM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   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----- From: Ben Winzenz [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 11:29 AM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC? 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: http://www.sunbelt-software.com/exchange_list_charter.htm