I'm trying to set up a Poweredge 2850 as a web server, but as a server novice it's causing me some confusion.

Its a virgin install so no data to be lost as yet, so I'd like to get the best arrangement for setting up Windows Server 2008. The box will run IIS, a mail and FTP server.

The current physical arrangement of the hot swap drives is

1 73GB   3 146GB   5 blank
0 73GB   2 146GB   4 146GB (but flashes green, amber off)

When I enter the PERC config screens on boot up I've got

   Raid Ch- 0

0 ONLIN A00-00
1 ONLIN A00-01
2 ONLIN A01-00
3 ONLIN A01-01

I think that drives 0 and 1 are set to RAID 1 and drives 2 and 3 are also set to RAID 1, certainly I can see 2 logical drives, both raid 1 of 69880MB and 139900MB

Now what I think I am getting here is that the 2x 73GB drives mirror each other and the 2x 146GB drives mirror as well? so by my noob thinking if a drive fails I can pull it, insert and new one and it will reduplicate from its matching pair?

I think the flashing amber probably indicates a failing drive in slot 4, should that just be binned?

What confuses me coming from a home user XP background is that when I load up Windows Server 2008 OS under my computer I only see a C drive of about 70GB capacity. i.e wheres the 146GB drive?

Any advice appreciated


Yeah, it sounds like 0 and 1 are RAID 1 (mirror) and 2 and 3 are also RAID 1. As for disk 4, take a look here. That is the manual for your 2850 and shows you what all the various blinking scenarios on the disks mean.

You mention you don't see the second RAID set in Windows. Are you just looking at Windows Explorer? If yes, that's normal. You need to launch Server Manager, navigate to Disk Management and there you should see the 146GB drive. Right-click it to initialize and format the disk and assign it a letter. Once it finishes formatting, you'll see it in Explorer just like the 73GB mirror.

  • Thats the pointer I needed to find it under disk management and format it. – Saul Mar 28 '10 at 13:24

If you've got a drive flashing, and you're not sure it's bad (it should mark it as failed in the bios setup screens), try swapping its place with another of the drives that bring up a green LED. If the amber light follows it, the drive is probably bad.

Assuming that's the case, you are left with 2 73GB drives and 2 146GB drives. Assuming that you don't have any to replace in the blank spaces, I'd do a RAID 1 of 73GB and a RAID 1 of the 146GB.

If you're going to use this for production, you're going to want at least one more 146GB drive to act as a hot spare. I believe that the 146 drives may be able to act as a hot spare to the 73GB mirror, but I'd test that before you rely on it.

If you're in a drive shopping mood, you should be able to find those at a relatively low price. Just search Google Shopping for the model, and you'll also need to search for "drive carriers" which are the sleds that the drives live in and allow hot swapping.

If you do end up buying more drives, forgo the 73 and just get the bigger drives, then make a RAID-5 array (with one hot spare). Although RAID-5 is generally frowned upon for "modern" drives, your 146GB drives will be fine.


OK, as icky2000 linked to, essentially drive capacity has exceeded the unrecoverable read error (URE) rate, so that "modern" drives (1-2TB+) in a RAID configuration are statistically likely to suffer an unrecoverable error during the RAID rebuild.

In other words, if a drive dies, and you get a failure during rebuild, your data is gone with RAID5.

  • I had previously moved the amber flashing drive around in the caddy and the flashing goes with it. It does not show as failed in the PERC setup screens though. So now I've got my 2 RAID 1 drives , 73 and 146 GB with drive letters assigned as C and E, is it best to leave C for the OS only and install other software or web root or databases to the E drive. Is there a best logical way which makes life easy in the future for backups etc – Saul Mar 28 '10 at 13:28
  • You can install apps on C but certainly put all the critical data on E. This will make backups easier and in the future if you should ever have to rebuild the OS you can do that without touching your critical data. – icky3000 Mar 28 '10 at 13:39
  • The dell manual says the flashing sequence means "predicted failure" though how they predict I don't know! It does not show as failed in the PERC setup screens though. Can such things be resurrected? – Saul Mar 28 '10 at 13:41
  • Matt: care to elaborate on the comment "Although RAID-5 is generally frowned upon for "modern" drives, your 146GB drives will be fine. "? – Keith Stokes Mar 28 '10 at 13:49
  • Keith, I'm not Matt but here's a intro to the issues with RAID 5 (he's discussing mostly SATA disks here but the same issues apply to enterprise disks too): blogs.zdnet.com/storage/?p=162. – icky3000 Mar 28 '10 at 14:13

You should try using Dell's installation CD/DVD for the install.

You simply boot Dell's disk, and it guides you through a graphical interface for setting up RAID and Windows itself. It is much more friendly than using the text interface at boot.

If you don't have it, download it at support.dell.com.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.