RAID Cards

[CFGuy]

After spending a whole weekend completely rebuilding my server, I've decided its time to setup a RAID. I'm not looking for lots of storage but want the safety of a RAID 1. I'll be using 2 60Gb hard drives. The motherboard in this computer does not have RAID built in so I need to get a card. This will be my boot up/operating system drive. I have an AMD XP 2.8Ghz CPU with an ASUS a7v8x-x motherboard running Windows Server 2003.

Later, (Much Later) down the road, I will want to add a second RAID for storing DVDs. I'll do a RAID 5 at that time and keep the RAID 1 for the operating system. The case is a full size tower and has slots for up to 10 hard drives. 11 if I remove the floppy drive.

Can I have 2 RAID cards? 1 now that handles 2 drives and later add one that can handle 8 drives.


Any recomendations for a good, low price card for the 2 drive RAID?

I was looking at newegg.

http://www.newegg.com/app/ViewProductDesc....-102-002&depa=0

http://www.newegg.com/app/ViewProductDesc....-102-007&depa=0

http://www.newegg.com/app/ViewProductDesc....-102-045&depa=0

 

[Rupp]

Jeff,
I've often wondered about RAID and what it offers via the various RAID levels. Can you tell me what a 2 HD RAID configuration buys me over say using something like Acronis True Image daily?

 

[electron]

Jeff, technically you can use more than 1 RAID card, but it all depends on how your motherboard deals with this, some of them just choke on them, some of them don't allow you to boot the other drivers, and others work fine, so it's more of a guessing game. If all you want to do is mirror the drives, you could do this with the OS as well (assuming 2003 still supports it), I have been doing this for a while now (even using Linux), and no problems at all.

Rupp, when you mirror a hard drive, and one of them dies, you can disconnect the dead drive, boot the machine back up from the second drive, and you are good to go.

I personally use Acronis for my machines at home so I can keep my systems as 'simple' as possible, and in many cases, when a HD gets corrupt, the corruption is copied to the second drive as well. Raid 1 is only useful if your hard drive dies, and no data was corrupted right before it died.

 

[CFGuy]

Rupp,
To buy True Image that will run on Windows 2003 costs $699.
I do have True Image and use it for my laptop and Home Automation server, but both of those run XP Pro.

From the reading that I have done so far.
RAID 1 - exact copy on two hard drives. One dies, the other one keeps your system running. You replace the dead one, and the RAID is rebuilt.
In my case I'm not worried about the down time, just the number of hours to install everything and get it setup.

RAID 5 - Makes several Hard Drives look like 1 big drive. You lose the space equal to one drive for the controller info but if 1 drive dies, you just replace it and it gets rebuilt. No wasted time re-ripping what was on it.

On all of my computers, I have mapped drive V for videos. This drive gets all the video we shoot with our camcorder and eventually all our dvds. I have 4 kids that want to watch different movies so a DVD changer won't work for us.


Electron,
I wasn't aware the OS could do that. I will talk to our system admin at work and see if he knows about 2003. Thanks!!

 

[DavidL]

My Server has the boot drive on Raid 1 with two SATA fast 160 gig drives. This has already helped me save my server install twice. My Gigabyte motherboard supports this standard. This is great if one drive fails.

It also has a 3ware Raid5 PCI card for Media storage in case one of those drives fails (no reripping).

I also use PowerQuest to image the boot drive onto another Lan connected PCs drive (for backup). This is used if something deletes a critical file. This "intentional" deletion will be replicated to the Raid1 mirror drive so Raid won't help here.

I also use Homeseer script for rotating backup to a third drive in the HS server. This is because I tend to mess up in Homeseer more than OS areas so I don't have to reimage the whole drive to fix a HS issue (that I messed up).

If the house burns down, I'm screwed. One of these days, I need to build an offsite (barn?) backup server...

 

[CFGuy]

I found a tutorial on how to setup Windows 2003 to mirror a drive.

http://thelazyadmin.com/2005/02/mirroring-...indows-2003.htm

 

[patsikes]

The "lost" drive on a RAID 5 setup is actually used to store the parity from all the other drives. This is what gives you the redundancy. Raid 5 is also a lot faster for reads than a single drive or RAID1 so it would be good for media or other data storage that needs quick reads.

How Parity Works:

In each bit of the extra drive, it stores a parity bit that is constructed by looking at the matching bits on all the drives. So if you have 5 disks (4 for data, one for parity), it looks at the same "spot" on all 4 disks, reads the bits and does a parity calc. So it you had:

DISK1        DISK2       DISK3      DISK4      PARITY
0             0            1          1           0
1             1            1          0           1

So if DISK2 drops offline, it can extrapolate based on the parity what each bit was on that disk...

The other thing that is cool with RAID 5 is that the parity information is actually spread across all the disks (non-dedicated parity drive) which helps with performance on rebuilds.

Amazing what you can remember after supporting HP NetServers for a couple years...an that was a long time ago...

Patrick

 

[Micah]

I built my media server with Windows 2000 Server software Raid 5.

My recommendation is NOT to do that. Windows RAID software is horribly slow compaired to Linux software and hardware. Also it doesn't support Online Capacity Expansion which in my book is an abolute must unless you're going to be maxing out the number of drives the controller supports from the beginning.

Something else to keep in mind, and this is a bit off topic, but when buying a case for your server you don't have to get the biggest case out there. You can buy various enclosures that will increase the number of drives a case can hold.

My personal choise for a RAID 5 controller is the Raidcore 8 port Sata Controller. They're a little pricey, but they're cheaper than buying 8 300GB hard drives all at once.

 

[CFGuy]

Micah,
Thanks for the links! I will keep the 8 port controller in mind when I get ready to start my storage for media files.

For now, I just want to mirror the operating system drive in case a drive dies.

My plan at this point (Subject to change - aren't they always) is to let windows 2003 handle the 2 60Gb HD in a RAID 1.
Then later in the year start building a RAID 5 using a controller and large drives. With the camcorder video and the movies that we already have, I would need 800 to 900Gb. That 8 port card you posted looks like the way to go at that time. Especially since it can run up to 4 of them. Gosh, can you imagine 32 of the 300Gb hard drives.

 

[CFGuy]

Ok, plans changed. I am getting one of these:

http://www.promise.com/product/product_det...&product_id=107

Got it on e-bay for $15. Figured anytime I can move the processing to hardware it leaves the CPU for more important stuff.

 

[Micah]

$15? Wow, nice find. Can't argue with that.

 

[electron]

Promise is pretty good, I have deployed it in server machines before. The software RAID mirroring will work fine if your machine isn't outdated, I have deployed many servers where the boot drives are mirrored that way. Of course, nothing can beat a true hardware controller, but if you want true speed and redundancy, you would be going with SCSI anyways

 

[huggy59]

FWIW, hardware RAID is always going to be faster, and IMO more stable and easier to recover, than software RAID. It takes almost no time to set up, except for initial formatting/striping/mirroring. In some cases, you can create a RAID 1 mirror AFTER you have a drive set up - the mirroring can be done by the controller in the background as the system runs. This is a great way to make a back up of a system while it is online. With a hot swappable chassis, it's really easy to do, too.

Personally, I have an Adaptec 1200A ATA RAID controller in my HS machine. It is working fine now with a pair of 160GB drives. The controller appears to the PC as a SCSI BIOS, so it loads early in the POST. This controller will handle four ATA drives - two on each controller cable - but doesn't do RAID 5.

As far as I know, since ATA drives are limited to two per cable, for anything more than RAID 1 (mirroring), you've got to go with SATA or SCSI. I don't believe there is any ATA controller out there that'll do more than that, but I could be wrong. I've never seen one.

Many newer M/B now come with SATA RAID capabilities. They may be limited to certain types of RAID, however, so read the specs carefully.

Under RAID 5, the minimum number of drives for true RAID 5 to work is 3. You lose a bit more than one drive's total space as you add drives, however. But the trade-off is that the system is fault tolerant for a single drive failure. If more than one drive fails at once, you're rebuilding from backup or scratch.

Now note, HOT SWAP is a feature of the chassis and controller that allows you to pull a drive or insert a drive while the power is on. This is usually a SCSI chassis system like those on big server systems. Also note that HOT SPARE is the term given to an extra drive that is available in case a drive fails in the RAID array. The controller can be set to rebuild the array AUTOMATICALLY when it detects a drive has died, and it'll use the spare drive. This does slow down the system a bit while the spare is built to replace the dead drive, but the system doesn't go down or lose data.

Now, RAID 5 is good for a lot of things, but for database systems such as MSSQLServer, which has the capability to stripe the data itself within the database, you may not want a RAID 5 array. It is not only not needed, but it can actually slow database performance and cause database corruption if writes are buffered improperly. But this depends on the type of database created under the SQL server. And certainly a single SQL server could have mutiple databases on different disk subsystems. Read the fine print!!

For a standard file server, such as for use as a video or music repository, RAID 5 is great. I have recently obtained a couple old Compaq ProLiant 7000 servers, each with 3 RAID array controllers and chassis space for 18 (3 x 6) SCSI drives, other than internal bays. One of these is now my audio file repository. I've set it up so the OS is on a set of mirrored drives, the big data areas are RAID 5.

Also be aware that some RAID controlers will not support the OS using software file system level compression of files and folders. Read the specs!

This page has a good explaination of RAID details: http://www.staff.uni-mainz.de/neuffer/scsi/what_is_raid.html

 

[bh00]

Hi,

Does anyone know where I could get the Broadcom BC4452 in the UK? They have a UK seller apparently but bugger me if I can find anything about buying their products on their site. Can't find anything on ebay or anything either.

Anyone have a ballpark figure for it too?

Ben