RAID options on PE2800 3

[SirBC]

I'm trying to configure a Poweredge 2800 on the Dell website with the following setup:

RAID 1 (2x36 GB) for OS
RAID 5 (4x36 BG and 1 hot spare) for data

But the only split backplane option I see is a "2X4 Hot-Pluggable Split Backplane,PE2800". Does that mean I can't have 2 ports on one channel and 6 on the other? Or is that something I would have to call and have them configure for me?

Thanks!

-Dave

 

[SirBC]

It's going on a shelf once I get it to my office

I am currently installing the OS and have a question.

I ordered the server without an OS, and with a 2x36 GB RAID 1 in the media bay, and a 3x26 GB RAID 5 with a global hotspare. I started by using the Dell OpenManage server assistant. It showed that I had the RAID 1 and RAID 5 arrays of correct size. I specified the boot partition size, SBS2003 OS, and off it went. Once the OS was installed and going through the setup, I got to the "Component Selection" screen, where you specify what compents you want installed and where you want them installed (eg, Exchange). However, only Drive C: was listed as an option for where I want to install components.

The Disk Manager shows:

Disk 0 (Basic) C: 34 GB NTFS Healthy (System)
Disk 1 (Basic) 67 GB, unallocated

So it looks like I have to first setup the drives on the RAID 5 array first.

I just want to be sure that what I did is correct. I did this:
1. Select disk 1 and and converted to dynamic disk.
2. Create a new volume on disk 1.

However, when I selcted New Volume, "Simple" was the only option offered. The RAID 5 option was greyed out. I went ahead and selected simple and it's currently formatting, but I'm worried I screwed something up??

 

[technome]

Good your placing it on a shelf. Agree with Twwabw, a server at floor level becomes an excellent dust filter.


One possible snag... you may need to go into the raid setup, and define which raid.. raid 1 or the raid 5 boots first

"but I'm worried I screwed something up??" You have not, your set to go

Dave, why are you going near DYNAMIC disks ?, 99.99% of server setups should not use dynamic disks. All that is needed is to create a new volume. You can not use the Dynamic disk option, as presently your array controller offers the space on the 3 raid drives as one big disk to the OS, Windows does not know anything about the raid 5 setup, and thankfully will not.






........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[SirBC]

I think I should probably start over then, since I converted the RAID 5 disks to dynamic. If I boot from the server assistant disk will that give me the option to format the drives on both arrays? The first time I did that I don't remember every seeing anything about formatting the RAID 5 disks, it only asked how big I wanted to make my boot partition.

 

[twwabw]

You can manage the array from the OpenManage Server Manager once the OS in installed. The server assistant is concerned with where and how you want to set up your OS and boot drives- it doesn't care about peripheral drives, which is what your Raid5 array is as far as it's concerned.

I would go ahead and install the OS on your Raid1 array using the SA cd, and yes- I would have it install the dianostic partition and utilities too. As you can see, you're already chasing the CD's anyway. Just be done with it- it doesn't hurt anything. That's my opinion.

Then once the OS is up and running, install the OpenManage application. This is the easiest way to manage your additional array. The current preferred method is to use the OpenManage app to manage your array, instead of installing the seperate Array Manager utility (which was the old way). Then through the app you can partition the array if you want and configure it.

You will not use Windows disk manager to manage the array, other than format the partition(s).

 

[SirBC]

I have already installed SBS2003, with the OS on my RAID 1 (C and data stores on RAID 5 (E. But during the SBS setup, I (stupidly) converted drive E: to a dynamic disk, then installed data stores on it. Since I can't convert a disk from dynamic back to basic, I would have to reinstall the OS to fix this, right?. Should I first format the E: drive using the OpenManage app, then reboot with the server assistant and begin again?

 

[twwabw]

When you say "data stores", what do you mean? Have you moved Exchange logs/store there? Or you just created a volume with nothing on it yet?

If there's nothing there, just delete the entire array, and re-create it, reformat it, reactivate it. You can do it all from Windows using the OpenManage app, if you've installed it. Like I said- I would.

 

[SirBC]

I put my exchange,user shared folders, and sql data stores there. I guess I'll just proceed as if there isn't anything there and reformat it, then reinstall sbs. Do I have to delete and re-create the array first? Can't I just reformat it as a basic disk?

 

[twwabw]

I would recommend starting from scratch, using the server ass't CD.

 

[xmsre]

I would recommend starting from scratch, using the server ass't CD."

I wouldn't.

The server assist CD uses an automated build process that starts with a FAT partition that is later converted to NTFS. This results in an allocation unit size for the NFTS partition of 512 bytes instead on the normal default of 4K. This has a severe negative performance impact for the OS, page file, and any applications that use the system temp directory.

Add to that your recommended RAID config, and you have snail. RAID 5 with 4 drives is actually slower that a single drive. I would use one big 0+1 set with all six drives and carve logicals from it. In fact, in recent tests with a 2850, one of my customers has documented a 400% performance increase by simply following these two recommendations.

And you're going to run SQL on it...

 

[technome]

RAID 5 with 4 drives is actually slower that a single drive."
The writes are nearly the same, extremely close, the reads on a raid 5, 4 disk array setup properly FAR surpass a single drive. Go to this site, show me where a single drive beats raid 5.

http://tweakers.net/benchdb/suite/13

Agreed, a raid 10, or as Dell decided to redefine the industrial standard as 0+1, is superior to raid 5. In an archive or situation which is not write intensive, raid 10 is overkill, but damn, I like the crisp desktop response of raid 10, server or wks.

I would like to point out, benchmarks stress a disk system. Most disk access do not resemble benchmark except in over stressed servers. Most people fail to realize raid 5's write performance is much better generally then benchmarks show, as the cache works much more efficiently on servers which are not over stressed.


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[xmsre]

I would like to point out, benchmarks stress a disk system. Most disk access do not resemble benchmark except in over stressed servers. Most people fail to realize raid 5's write performance is much better generally then benchmarks show, as the cache works much more efficiently on servers which are not over stressed."

One thing to point out, the system temp directory is on the system drive by default. Applications that use the system temp directory, Exchange for content conversion, some antivirus scanners, etc., will certainly stress the system disk. Also, at least a portion of the page file resides on the system disk. With a allocation unit vice the 4K default, paging activity will stress the system disk. When an IO larger than the allocation unit size hits the FS driver, it's split into multiple smaller IOs. You can view this in perfmon. The counter is Physical disk - Split IO per second.

 

[technome]

Xmsre, how long have you been doing this type work..it can't be long.



........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[xmsre]

Since the mid 90's. Used to be a smoke jumper for MS, for critical situations - Sev A & Sev A-1. Did some time subcontracting for Dell and EMC, a short stint with the MS/Accenture stepchild, and now work for a storage company.