Upgrading RAID -- Controller AND Drives

[akshatp]

Current situation is server with three 146GB Seagate drives attached to a CERC 1.5/6ch SATA RAID controller (made by adaptec?). Windows 2003 OS serving primarily as an EXCHANGE server.

Running a RAID 5 array right now, total volume around 297GB (110GB used)

I ran a throughput test and got around 3 mb/sec, which is extremely slow, presumably due to the RAID controller attached to the 66 mhz PCI slot but also the older drives.

I want to upgrade the drives anyway, as they are nearing 5 years old and I would rather replace them before they fail; and also the controller to get a performance boost.

The server in question has two 64-bit PCI-X and two PCI-E (4x & 8x) slots available for a shiny new controller, to go along with new 1TB WD Black HD's.

Now, my questions:

1) Should I keep the same RAID 5 array with the new setup?
2) How would I achieve my goal (going from existing array to new array) in the shortest time possible, with the least amount of headache, and absolutely zero data loss?
3) What RAID controller should I get (Under $200 if possible)

I am not sure whether I should swap in the new drives to the existing controller one at a time until the array is on the new drives, and then just swap controllers? (Doesnt sound like it would work)
or
Can I take a "clone image" of the existing array and just throw it onto a new array? (Will the new controller/hd's security identifiers cause a problem?)
or
I also have a DLT backup system, so could I take a "snapshot" of the current OS partition and back it up to tape and restore to the new hardware? The tape is 80/160 and current usage is just about 110GB.

Last piece of info: The array is split up into two partitions (OS and Data)

Any help is greatly appreciated in helping me get this done.

 

[RebateMonger]

I just used HDTune 2.55 to measure the Transfer Rate on a Dell PE 1800 with the CERC SATA 1.5/6ch RAID card with two 160 GB SATA disks circa 2006 and got 45 Megabyte/sec transfers. These are in RAID 1 and not RAID 5. The card is running on a 66 Mhz 64-bit PCI slot.

You aren't going to find a decent RAID 5 controller for $200. More like $400 with a BBU.

A new disk controller is going to generate issues. The server won't boot to the new controller without special effort. Fortunately, with both new disks and a new controller you can always go back to your original configuration if you have problems. There's backup software (StorageCraft's and Acronis') that are capable of doing a restore to different disk controllers. Maybe your backup software can do this, too.

The cheapest and easiest would be to keep the Dell controller and install four enterprise-level disks in RAID 10. That'll be faster than RAID 5 and safer, too. Although that generation of Dell controller isn't known for its speed, it takes very little to manage a RAID 10 array.

WD RE3 250 GB Enterpriise disks are $65 each. So that's $260 for a 500 GB RAID 10 array with four Enterprise disks. You can add a hotspare for $65 more if you have space for it.

If when it's all done it's not fast enough for you, you can still buy that $400 RAID controller and migrate Windows to the new disk controller, but it's a PITA if you don't have the right software tools.

You'd make records of all the settings on the Dell controller, back up the entire system, insert the new disks, create the new arrays, and restore the two volumes to the new arrays. Presumably you'd increase the size of your OS partition before you do the restore, since most folks undersize this at first install.

Note:
Out of curiousity, I ran HDTune 2.55 against a single WD 750 GB SATA disk (one of four that are hot-swapped for backups) on that same server. This disk is controlled by a cheap PCI-Express Silicon Image 3132 SATA disk controller. I averaged about 70 Megabytes per second across the disk.

 

[akshatp]

I just used HDTune 2.55 to measure the Transfer Rate on a Dell PE 1800 with the CERC SATA 1.5/6 RAID card with two 160 GB SATA disks circa 2006 and got 45 Megabyte/sec transfers. These are in RAID 1 and not RAID 5.

You aren't going to find a decent RAID 5 controller for $200. More like $400 with a BBU.

A new disk controller is going to generate issues. The server won't boot to the new controller without special effort. Fortunately, with both new disks and a new controller you can always go back to your original configuration if you have problems. There's backup software (StorageCraft's and Acronis') that are capable of doing a restore to different disk controllers. Maybe your backup software can do this, too.

The cheapest and easiest would be to keep the Dell controller and install four enterprise-level disks in RAID 10. That'll be faster than RAID 5 and safer, too. Although that generation of Dell controller isn't known for its speed, it takes very little to manage a RAID 10 array.

WD RE3 250 GB Enterpriise disks are $65 each. So that's $260 for a 500 GB RAID 10 array with four Enterprise disks. You can add a hotspare for $65 more if you have space for it.

If when it's all done it's not fast enough for you, you can still buy that $400 RAID controller and migrate Windows to the new disk controller, but it's a PITA if you don't have the right software tools.

You'd make records of all the settings on the Dell controller, back up the entire system, insert the new disks, create the new arrays, and restore the system to the new arrays. Presumably you'd increase the size of your OS partition before you do the restore, since most folks undersize this at first install.

45 MB/Sec transfers??? Read or write? Do you think the RAID 5 is slowing me down?

Thanks for the info, I will look into keeping the existing card and going with Enterprise drives. I notice the RE3 are only 16MB cache. The WD Black's are 32MB. Are the RE3's built better? Will the 1.5 card utilize the 3.0 GB/s of the Re3's?

EDIT: Interesting, using HD Tune I get 35 mb/sec read speeds. I was using "throughput tester" before.

 

[RebateMonger]

45 MB/Sec transfers??? Read or write? Do you think the RAID 5 is slowing me down?

HDTune 2.55 only measures read speeds. RAID 5 is always significantly slower on writes, even with the best of RAID cards (which you don't have). That's why you should use RAID 1 or use RAID 10 if you want faster writes. RAID 10 writes will be significantly faster if you want the extra speed and it's very low cost in your case.

In my opinion, there's no reason for you to be running RAID 5 on your server. If you have space for four or five disks, just move to RAID 10, with hotspare if you have room for the extra disk.

If you have special speed needs for the second array, you might also think about two RAID 1 arrays (using two disks each). That'd be something you might use if you do a lot of database access with the database on the second pair of disks. But RAID 10 would be faster overall.

 

[akshatp]

HDTune 2.55 only measures read speeds. RAID 5 is always significantly slower on writes, even with the best of RAID cards (which you don't have). That's why you should use RAID 1 or use RAID 10 if you want faster writes. RAID 10 writes will be significantly faster if you want the extra speed and it's very low cost in your case.

In my opinion, there's no reason for you to be running RAID 5 on your server. If you have space for four or five disks, just move to RAID 10, with hotspare if you have room for the extra disk.

The server has space for 4 disks in the cage, and at least one more inside, so I could definitely go with the 4+1 RAID 10 that you describe.

No special needs for the 2nd array, so the RAID 10 will be fine.

But the question is, how would I go from the R5 to the R10? Can I add the disks and do it on the fly using Dell OpenManage and then slowly remove the old disks? Sorry for the n00b-like questions, I was the one who set this up 5 years ago, but haven't messed with it since.

Also, any downside to getting the 320GB or 500GB RE3's? Noticed they are only 16MB cache opposed to the 32MB on the 1TB drives though 🙁

 

[RebateMonger]

Going to four brand-new disks minimizes the risk of the migration since you can go back to where you started if things go wrong.

As I described earlier, you'd need to make full system backups. I'd make two, preferably using different backup technologies. This will be an opportunity to see if your backups are any good for restoring your system.

Be sure to write down ALL RAID parameters for your current array(s). Read the controller manual and understand how you will get back to where you started if you need to re-insert your RAID 5 disks.

Then you carefully label and remove the RAID 5 array and connect the four new disks. Boot to the array management and create a RAID 10 array with the four disks. It may take a while for them to be initialized, but nowhere as long as it'd take a comparable RAID 5 array.

Now do a full system restore from your backups. How you do this will depend on your backup software. You'll need to create appropriate volumes to hold your two volumes and, as I mentioned, you may want to increase the size of your System partition at the same time, since you have 200 GB extra space (if you use 250 GB disks).

Regarding the use of Enterprise disks:
Most disk makers now only certify the use of their Enterprise-grade disks for use with RAID arrays. Enterprise disks work better with RAID controllers to lessen the chance of a disk dropping from the array in case of read errors. Many also have better vibration sensors. You can get WD 1 TB Enterprise SATA disks for $130 each if that's what you want. I just bought a couple of them from Newegg last week. Yeah, I've gotten away with 1 TB WD "Green" disks in RAID 1, but I'm not sure it's worth taking any risks now that disk prices are lower.

 

[akshatp]

Going to four brand-new disks minimizes the risk of the migration since you can go back to where you started if things go wrong.

As I described earlier, you'd need to make full system backups. I'd make two, preferably using different backup technologies. This will be an opportunity to see if your backups are any good for restoring your system.

Be sure to write down ALL RAID parameters for your current array(s). Read the controller manual and understand how you will get back to where you started if you need to re-insert your RAID 5 disks.

Then you carefully label and remove the RAID 5 array and connect the four new disks. Boot to the array management and create a RAID 10 array with the four disks. It may take a while for them to be initialized, but nowhere as long as it'd take a comparable RAID 5 array.

Now do a full system restore from your backups. How you do this will depend on your backup software. You'll need to create appropriate volumes to hold your two volumes and, as I mentioned, you may want to increase the size of your System partition at the same time, since you have 200 GB extra space (if you use 250 GB disks).

Regarding the use of Enterprise disks:
Most disk makers now only certify the use of their Enterprise-grade disks for use with RAID arrays. You can get WD 1 TB Enterprise SATA disks for $130 each if that's what you want. I just bought a couple of them from Newegg last week.

I saw the 1TB, thats overkill. The current usage is just about 35% on the existing 300GB array. Space is not the issue here, I will probably go with the 320 or 500 GB drives.

Really appreciate your help. I am going to purchase the drives and attempt this migration on the 18th.

 

[akshatp]

Consider this scenario and tell me if it would work:

For this scenario, lets just assume I already have a good backup of the Data partition and only need to transfer the OS partition

1. With the existing array still in place, add ONE of the new drives to the non raid sata port right on the motherboard.
2. Clone the existing OS partition to the single drive.
3. Remove existing array
4. Install and configure new drives in RAID 10 and create partitions
5. Clone the single drive back to the new array

Would I be able to then remove the single drive (for later use as hot spare) and boot from the newly cloned array? Would this work?

 

[RebateMonger]

Really appreciate your help. I am going to purchase the drives and attempt this migration on the 18th.

Good luck. As I noted, this should be a VERY low-risk operation as long as you label your old disks and cabling so you can get back to where you started if you have to. I had to do this once because, when I got everything restored to a brand-new set of disks and a brand-new RAID card, several programs on the client's server weren't working correctly. After putting everything back the way it was, the next day I learned that those programs WEREN'T WORKING on the "old" server, either.

It wouldn't hurt to check the overall health of the server before doing the migration. You may want to scan the current array for errors, too. These things can be done in advance and can avoid programs during/after the migration.

Please take the time to study your RAID card's manual. When you are half way into the migration is NOT the time to learn how your RAID card works. Do your homework on this one. There are TONS of those cards out there, so if you don't understand how to do something you should have time to ask in advance.

 

[akshatp]

Good luck. As I noted, this should be a VERY low-risk operation as long as you label your old disks and cabling so you can get back to where you started if you have to. I had to do this once because, when I got everything restored to a brand-new set of disks and a brand-new RAID card, several programs on the client's server weren't working correctly. After putting everything back the way it was, the next day I learned that those programs WEREN'T WORKING on the "old" server, either.

It wouldn't hurt to check the overall health of the server before doing the migration. You may want to scan the current array for errors, too. These things can be done in advance and can avoid programs during/after the migration.

Please take the time to study your RAID card's manual. When you are half way into the migration is NOT the time to learn how your RAID card works. Do your homework on this one. There are TONS of those cards out there, so if you don't understand how to do something you should have time to ask in advance.

Excellent advice, I will be sure to do my homework beforehand. The server is in otherwise perfect health, and I started a consistency check on the current array about 3 hours ago. Its about 25% done.

What do you think about my hypothetical scenario two post above?

 

[RebateMonger]

Consider this scenario and tell me if it would work:

For this scenario, lets just assume I already have a good backup of the Data partition and only need to transfer the OS partition

1. With the existing array still in place, add ONE of the new drives to the non raid sata port right on the motherboard.
2. Clone the existing OS partition to the single drive.
3. Remove existing array
4. Install and configure new drives in RAID 10 and create partitions
5. Clone the single drive back to the new array

Would I be able to then remove the single drive (for later use as hot spare) and boot from the newly cloned array? Would this work?

Offhand (it's getting late), I think you could do it that way as long as the cloning software is capable of talking to the disk controllers. Having extra disks and not touching the original disks gives you a lot of leeway to play.

Be careful with any cloned OS disks. Do NOT try to boot the server with both an original OS disk and its clone available to the server at the same time. Windows DOES NOT LIKE THIS and you probably won't like the result, either. To be safe, before adding the disk as a hot-spare, you may want to attach it to another PC and delete the partition(s).

OK, I'm out of here. I'm sure some other folks will have suggestions, maybe better than mine.

Please follow up here with your progress and final results, hopefully including disk transfer speeds with your new array(s).

And you never did mention what the server model is?

And, yeah, I'd just go with the WD 500 GB disks at their $78 price. That'll give you a 1 TB RAID 10 array with 5-year disk warranties. That'll give you plenty of extra space while still giving reasonably fast and safe array rebuilds when a disk fails.

 

[akshatp]

And you never did mention what the server model is?

Dell PE 1800 with the RAID controller in the 66 mhz PCI 64 bit slot 🙂
With three 146 GB drives, circa 2006. Same as the setup you tested on.

 

[RebateMonger]

Dell PE 1800 with the RAID controller in the 66 mhz PCI 64 bit slot 🙂
With three 146 GB drives, circa 2006. Same as the setup you tested on.

If you get a chance, download HDTune 2.55 (the free read-only version) and see what readings you get.

BTW, I'm assuming your disks are actually 160 GB SATA disks. 146 GB disks were only SCSI disks as far as I know. And SAS.

 

[akshatp]

Well, the day has come. Ill be performing the work tomorrow. I have purchased and installed EASEUS Partition Master Server Edition, and it successfully read my existing array. With it, i will copy the entire disk to a new single SATA drive, remove the existing drive array, build a new RAID 10 array, and copy the data back. Easier said than done, I know, my main concern is I hope I am able to boot off of the single drive. If that works, i should be good to go.