RAID configuration on Exchange
I've sifted through many of the previous posts about RAID on Exchange, but figured I'll ask my own way. My users are getting the server busy balloons in Outlook throughout the day. Reading through performance documents on Exchange I've done some performance monitoring and see many spikes in disk sec/byte and RPC latency leading me to believe the performance is disk related.
My Exchange server has 4 36GB disks in one array with spare. It's RAID 5, one logical disk.
Would I benefit by reconfiguring someway or another? Creating two disks, going to RAID 1, etc.? Suggestions?
My Exchange server has 4 36GB disks in one array with spare. It's RAID 5, one logical disk.
Would I benefit by reconfiguring someway or another? Creating two disks, going to RAID 1, etc.? Suggestions?
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I have no idea who set this up this way (etiher the guy before me or the consultant he used) but I figured it wasn't done right. Not a lot here is! ;)
abraham808: the article you linked me to after reading it, I get the sense that a minimum of 6 physical disks are needed, 2 for each RAID group (OS, SG, DB). Right? No one has a mailbox as large as 1GB (close, but not quite). I've limited sizes to keep them low, and can't get it across to them that large mailboxes = low performance!
Both: so if (or when) I reconfigure the server, having only 4 physical disks w/ no room for expansion, I would want the OS and SG on one pair of disks, RAID 1; and the database on another pair RAID 5?
abraham808: the article you linked me to after reading it, I get the sense that a minimum of 6 physical disks are needed, 2 for each RAID group (OS, SG, DB). Right? No one has a mailbox as large as 1GB (close, but not quite). I've limited sizes to keep them low, and can't get it across to them that large mailboxes = low performance!
Both: so if (or when) I reconfigure the server, having only 4 physical disks w/ no room for expansion, I would want the OS and SG on one pair of disks, RAID 1; and the database on another pair RAID 5?
In an ideal world you would have three arrays. However with smaller sites you can get away with two. I don't know what you are referring to as "SG", but you need to have the transaction logs and the database on separate drives. The transaction logs will share the same array as the OS. However in that scenario what I do recommend is that the drive is partitioned. The transaction logs then have their own partition (in a directory). Then if something goes wrong with Exchange (email loop for example) which generates a large number of logs, it only fills its own partition up, not the drive the OS is on. Trying to get Windows to start on a machine with no free disk space at all is somewhat of a challenge.
Simon.
Simon.
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"SG" is from the link provided by abraham808, SG = Storage Group = Tx logs.
Hmmm, this could be a tight squeeze with 4, 36 GB disks, right? How would I reconfigure "in place"? Would I be able to make a backup of my Exchange, reconfigure the arrays and drive, reinstall Exchange and the restore the backup? Would that work restoring to a different drive configuration?
Hmmm, this could be a tight squeeze with 4, 36 GB disks, right? How would I reconfigure "in place"? Would I be able to make a backup of my Exchange, reconfigure the arrays and drive, reinstall Exchange and the restore the backup? Would that work restoring to a different drive configuration?
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Check....stop....rewind.
Duh! I started pictuing my server in my head and remembered I DO have two open slots for drives.
My question about backup, reconfig, restore still needs an answer though.
Duh! I started pictuing my server in my head and remembered I DO have two open slots for drives.
My question about backup, reconfig, restore still needs an answer though.
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So I understand you correctly: I buy two large disks and install them in the two avail slots. I create a new array with those disks, and set it as RAID 1. I then move my database(s) to those new volumes and keep the others as is?
If you are unable to do a swing migration so the entire server can be rebuilt, then what you have written will work.
Simon.
Simon.
Now the problem is how to reconfigure the server. You cannot reconfigure RAID on the fly, so you could be looking at some kind of migration using a staging machine so the original machine could be rebuilt. If you don't have any budget for additional disks, then two mirrored arrays would be better than what you have now - presuming that the database will fit.
Simon.