RAID 1 OS / RAID 5 Data: Same or separate arrays?

[Josh Dunbar]

Hello,

How do I need configure RAID 1 for the OS and RAID 5 for my data? I thought I set it up correctly before, but after deploying the OS and going to Disk Management, I don't see my RAID 5 array. It just shows as unallocated space. I have 5 disks total in this server. 2 are RAID 1 (OS); the other 3 are RAID 5 in a separate array. Do I need to configure these two RAID types in the same array or separate arrays? I did them separately, but something is amiss if I can't see my RAID 5 volume in Windows. Please advise a solution. Thanks!

[Josh Dunbar]

Wanted to add a few more comments:

I configured both of the arrays at the same time using the SmartStart disc. The first two discs are RAID 1, the remaining three are RAID 5. I configured these on separate arrays. If this is not the correct way to setup this configuration, please comment below.

P.S.: Can you edit your own forum posts?

Thanks,

Josh Dunbar

[Michael A. McKenney]

Two arrays. RAID 1 or 10 for OS. I would do RAID 10 for data, the write performance is faster and you lose 5% on read performance over RAID 5. RAID 10 will require 4 disks. You might also want to place your paging/swap file in its own RAID 10 array. You can expand/shrink partitions in Windows 2008 that don't have a paging/swap file. It will also keep your OS from fighting for r/w with paging/swap.

[Josh Dunbar]

Michael,

Thank you for your reply.

I only have 5 drives total, so RAID 1 & 10 together is out. Also, I need to know why my RAID 5 array is showing as unallocated space in Disk Management. The only options I get when clicking on that unallocated space are "New Simple/Striped/Mirrored Volume", & properties. RAID 5 is grayed out. It does not show a drive letter, either. Do I need to format the RAID 5 array from SmartStart or BIOS to make this work?

Regards,



Josh Dunbar

[Michael A. McKenney]

You did hardware RAID 5 on a controller. You are not doing software RAID in Windows so you don't get RAID setup. So just create your extended/logical drives. I don't use primary for non-OS partitions.

You never want to put hardware RAID and software RAID together.

You should see your RAID 5 unallocated partition, it would be 2/3 total of the three drives.

[Ali]

Hi Josh,

Keeping the Raid 1 and Raid 5 in different arrays is the correct way of doing it.

As you mentioned both the volume were configured at the same time, so I am assuming you don't have anything to loose in Raid 5

let me clarify the Raid setup here: H/w Raid configured on the smart array controller does not do partitioning Infact OS reads the H/w Raid volume as a single physical disk.

So, you need to allocate space in new partition, assign a drive letter and format them in order to use the space for data.

Before doing that, I would suggest you to verify your Raid configuration in HP ACU utility and make sure there isn't any expand/extend operation is running and you have healthy and two seperate logical volume.

You May refer to ACU guide for raid configuratiion
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00729544/c00729544.pdf

hope this helps,

thanks,
Aftab

[gregersenj]

Josh, as I read your post and replies, you have done most things correctly.

You have createt a RAID 1 for the os, and installed the OS.
You have createt a RAID 5.
Windows show the RAID 5 as unallocatet space!.
All you need to do is format it in Windows.

Open disk manager.
Right clik
Choose what volume type you want. Do read the windows manual !!
Just go ahead and try if you have doubts. Foa sa long as the server is not in produktion, and no data is at risk. Now is the time to play with.

BR
/jag

[gregersenj]

http://technet.microsoft.com/en-us/library/cc754936.aspx

Try to follow the add new disk links.

And as mentioned by the other helpers.
Your RAID 5, do appear as a physical single disk.

BR
/jag

[Josh Dunbar]

Gregersenj,

I am not able to format the volume from Disk Management. The option does not appear. Not even as grayed out. The only options I have available with the RAID 5 unallocated space are: New Striped/Spanned/Mirrored Volume. Format is not listed there. Would Diskpart work from the command prompt?

By the way, this server is a domain controller. I meant to mention that in an earlier post. I was told RAID 1 + RAID 5 would be the best setup for a DC build. Please correct me if I am wrong.

Thank you,



Josh Dunbar

[Ali]

Hi Josh,

I overlooked this info
" The only options I have available with the RAID 5 unallocated space are: New Striped/Spanned/Mirrored Volume"

Windows reads h/w raid as basic disk. however gives you an option to also convert it to dynamic disk... this means software raid over h/w raid which is not suggested.

I guess, something wrong here as it's not allowing to assign a drive letter to unallocated space.
What is the server and Controller model?

Verify your Raid 5 volume from ACU and use windows Setup to create partition on raid 5 volume and format them. exit windows setup without continuing the install process.

Another option that you can consider is to remove array and raid 5 volume and re-create them.

By the way, this server is a domain controller. I meant to mention that in an earlier post. I was told RAID 1 + RAID 5 would be the best setup for a DC build. Please correct me if I am wrong.

Raid 1 is the ideal raid level for Operating system as it gives better fault tolerance and read/write performance than raid 5. So you are right saying that!

Thanks
Aftab

[gregersenj]

It seem he has assigned it as a dynamic disk.

That's why he get that menu.

Possibility is to:
1. Convert it to a basic disk.
or
2. Continue with it as a dynamic disk.

>Josh.

Study the link that I postet in my first reply.
It's all in there.


I can't answer your question, on whats the best choice on the RAID level.

But if you want to change the RAID level later. You can add 1 more disk, and convert to RAID 1+0. It does require a BBWC installed, if it's a Smart Array E or P model.

BR
/jag

[Michael A. McKenney]

Did you create the RAID 1 and RAID 5 on a hardware RAID controller or on JBOD in Windows?

[Josh Dunbar]

To all,

It appears my array has fixed itself. I rebooted the server this morning when I got in and voila! Create Simple Volume appeared. So, I went ahead and formatted as NTFS and assigned a drive letter. I believe I can take it from here.

I had never done a "nested" RAID configuration before, so this was a learning opportunity for me. Thanks to everyone that assisted me with this.

Case closed.

Best regards,



Josh Dunbar

[gregersenj]

You're welcome.

If reboot, solved everything.
You could have done a rescan, in device manager. I guess.
(That idea didn't come to my mind)


BR
/jag

[Damien74]

hello, I am having a very similar issue/problem. I am trying to setup a raid 5 on my esata external drive enclosure using 5 2tb drives. I used the the raid card and utility that came with the enclosure and card to create the raid set. However, in windows disk management it would see my raid set as two separate volumes instead of one 7.2tb volume. On the left under disk it sees the whole 7.2tb but it lists a 2tb and 5.2tb listed as unallocated space. The 2tb will allow me to create a simple volume but the other doesn't allow me to do anything. I really want it to be a single 7.2tb disk. OS is Vista 64. Any ideas would be helpful. Thanks

[Michael A. McKenney]

hello, I am having a very similar issue/problem. I am trying to setup a raid 5 on my esata external drive enclosure using 5 2tb drives. I used the the raid card and utility that came with the enclosure and card to create the raid set. However, in windows disk management it would see my raid set as two separate volumes instead of one 7.2tb volume. On the left under disk it sees the whole 7.2tb but it lists a 2tb and 5.2tb listed as unallocated space. The 2tb will allow me to create a simple volume but the other doesn't allow me to do anything. I really want it to be a single 7.2tb disk. OS is Vista 64. Any ideas would be helpful. Thanks

With Hardware RAID 5, it is done at the controller level. Windows will only see a single huge unallocated space. You need to partition the space just like you would a normal hard drive and format it. 8TB could take 2-3 days to format. You controller might only be capable of a maximum of 5 TB. Many low end RAID controller have this limit. You will have to partitions on your RAID 5 array.

Don't install Vista or any OS in RAID 5. OS and Paging/swap files need RAID 1 or 10. Microsoft does not support RAID 5 for them. RAID 5 writes are too slow for OS and paging file. It can also corrupt the OS on boot up. I would consider doing RAID 10 + spare drive for your OS/paging file.

[Ali]

Hi Michael,

I guess its windows boot/mbr partition limitation. windows does not accept more than 2 TB as ntfs parition you need to convert it to GPT partition in order to utilize full space.

ref.. : http://support.microsoft.com/kb/946557

http://www.microsoft.com/whdc/device/storage/LUN_SP1.mspx

GPT
http://www.microsoft.com/whdc/device/storage/gpt_faq.mspx

thanks,
Aftab

[Damien74]

Thanks for the suggestions. The OS will not be part of the raid set, it is for data/media only. I was looking into the mbr vs gpt thing but can't seem to get disk management to let me even modify anything on that disk/raid set. I have ordered the newer model of my external drive bay enclosure which might solve my problem. It uses dip switches to setup the raid rather than bios or drivers.

[Ali]

Hi Damien,

You may create a seperate thread so that other people can also participate and advice you best and possible way to do that.

I would suggest you to try the software options first before getting the whole h/w replaced.

Windows disk management should provide you option to convert it to GPT.. if it is not allowing you to do that then It could be some issue with the windows itself.

I remember there was a hotfix for this issue for windows 2003 server but I am not sure whether this is also applicable in your environment.
ref.. : http://support.microsoft.com/kb/919117/en-us

If you have support from microsoft, log a call with them and also make sure you have all the latest hotfixes, service pack installed.

there are CLI based utilities as well which can help you convert GTP partitions.

if your h/w bios/utility show the correct value and healthy Raid volume then it may not be issue with h/w

thanks,
Aftab

[Damien74]

I GOT IT! Eventhough I was selecting GUID and not MBR when initializing the disk/raid set, it was still seeing it as a MBR disk. Went into diskpart and selected the disk and used the "convert gpt" command and BAM it sees the entire 7.2gb! Thanks for all your suggestions. I guess now i'll just have an extra external 5 bay enclosure since I already ordered a replacement. Oh well.