Re: Converting RAID0 -> RAID1 (281 Views)
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Occasional Contributor
BR78669
Posts: 5
Registered: ‎06-06-2002
Message 1 of 6 (281 Views)

Converting RAID0 -> RAID1

Hello.

I'm planning to install two new disks in a LH3 Netserver using a netraid 1M controler.
For the moment The machine use two disks (9GB, 36GB) in a RAID0 system without mirroring. The new disks having the same capacity as the installed disks.
For mirroring I want change the Raid level from 0 to 1 (If possible without loosing data).
Is it possible?
What's the right way to do this?
The server use Netware 5.0 Sp6a.

Thanks in advance for your advice.

Best regards.

Dirk Emmermacher
Dirk Emmermacher
Honored Contributor
Dave Unverhau_1
Posts: 741
Registered: ‎12-14-1999
Message 2 of 6 (281 Views)

Re: Converting RAID0 -> RAID1

Dick,

What is the size of the raid 0 logical drive? How much data does it actually contain? Is it the boot drive? Assuming that it's a 9GB LD (or smaller) and you have the empty slots for the two new drives, the right way to accomplish this is to back up the data, add the new drives and create a RAID 1 LD using the two 9GB drives. Then you can use the two 36GB drives for your remaining LDs.

If the LD in question is the boot/system drive, you will need to back up and restore in such a fashion as to make the new LD bootable (I'm not a Novell-savvy guy -- sorry).

If your current raid 0 LD is not your boot/system drive, you might prefer to build a new raid 1 LD on the two 36 GB drives and then copy the data from the old LD to the new one online (I'd still make a backup of the data.) I'm not sure how NetWare 5 handles drive letter assignments, but if it lets you choose the assignments, you could swap the drive letters after copying the data and then get rif of the old LD after verifying that you can see the data correctly on the new LD.

Regards,

Dave
Romans 8:28
Occasional Contributor
BR78669
Posts: 5
Registered: ‎06-06-2002
Message 3 of 6 (281 Views)

Re: Converting RAID0 -> RAID1

Hi Dave.
Thanks for your answer.

The 9GB Device is the bootdisk. There are round 7GB Data on it.

There are enough empty slots in the machine.

The server started with this drive. The 36 GB drive was added several years later.

What's about a RAID10?
A colleague had this idea yesterday. He would add the two new disk as Raid0 too and build a Raid10 with both LD's

Or as in the case installing a raid1 system: When I make a desaster recovery-tape (with Arcserve IT6.6) the system will recover the data on the system right?

Best regards from Hannover.

Dirk Emmermacher,
lowersaxony gymnastics federation
Dirk Emmermacher
Honored Contributor
Dave Unverhau_1
Posts: 741
Registered: ‎12-14-1999
Message 4 of 6 (281 Views)

Re: Converting RAID0 -> RAID1

Dirk,

In the NetRaid world, RAID10 is known as a "spanned array". While it has some advantages, I don't think you would derive any benefit with the drive complement you have.

I'm a little confused about your current "RAID0" configuration. If your 9GB drive is truly striped with your 36GB drive in a RAID0 configuration using the NetRaid controller, there is 27GB of unused space on the 36GB drive that cannot be utilized. This is because the NetRaid controller treats all drives in an array as the same size. So, in order to stripe the 36GB drive with the 9GB drive, it can only use 9GB if the big drive.

It sounds like availability of data (redundancy) is more important to you than the extra performance of RAID0. I believe your best choice is to Mirror your old 9GB drive to the new 9GB drive and do the same with the 36GB drives. If you need more capacity than the 45GB that this configuration will provide, I would opt for mirroring the 9GB drives (RAID0) and putting the critical stuff there, and striping the 36GB drives (RAID0). This will give you 9GB of redundant data and 72GB of "fast access" data. Just make sure that you use the RAID0 array for data that gets backed-up regularly and that will not seriously impact your business (critical applications keep running) in the event of a disk failure.

The NetRaid controller can convert a RAID1 array to RAID0, but I don't think it will convert in the other direction. Your best procedure will be to use a disaster recovery tape as you suggested.

What I would do is to shut down the system after making the recovery tape and remove the existing drives. Then install the new drives and use them as JBOD (no RAID). Then restore the data to these disks as desired. Once you have recovered the data, boot the system and make sure everything works as it should and you see all of your data where it should be. At this point, you can add the original drives and use the online NetRaid configuration utility to mirror the new disks back to the old ones, creating the RAID1 arrays (or stripe them, if you prefer).

You might want to read more about RAID levels and how the NetRaid controller implements RAID in the Installation and Configuration guide. It does a better job of explaining things than I can. Here's a link to the PDF document:

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Glueckliche Gruesse aus Albany, NY USA!

Dave
Romans 8:28
Occasional Contributor
BR78669
Posts: 5
Registered: ‎06-06-2002
Message 5 of 6 (281 Views)

Re: Converting RAID0 -> RAID1

Hi Dave.

I read your advice. So I will think about it very well.
You're right when you say redundancy is more important for me. I will have a look in the pdf-file (THX for the link) First I will start to make a recovery tape. Then I will start the job after a great cup of coffee.

Thanks for your help.

Best regards.

Dirk Emmermacher

P.S.: Can I ask you directly?
mailto:Dirk.Emmermacher@ntb-infoline.de
Dirk Emmermacher
Honored Contributor
meloni
Posts: 817
Registered: ‎07-02-2001
Message 6 of 6 (281 Views)

Re: Converting RAID0 -> RAID1

assuming you have:
LD0 raid 0 with one 9 gb hdd capacity 9 gb
LD1 raid 0 with one 36 gb hdd capacity 36 gb

you can add one 9 gb and one 36 gb drive in order to have:

LD0 raid 1 with two 9 gb hdd capacity 9 gb
ld1 raid 1 with two 36 gb hdd capacity 36 gb

to reach this :
Make a full backup (just in case)
add the two new disks
start from cd navigator and run netraid assistant
you will see the previous config plus two new hdd
start wizard, then drag and drop the 9 gb hdd in the LD0, you will be prompted if you wand to expand the raid 0 or create a raid one, select raid level one, and data will be mirored in the second hdd.
when finished do the same for the 36 gb hdd

bye
marino
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