[NDBounce]

I am new to servers. My questions refer to a PC server, but I'm sure people here can help explain this to me:

1) What is RAID, and in particular RAID 5
2) Is there a formula to help determine how much drive space you will get off a RAID drive? ie Our office has a server with 3 9GB drives in a RAID 5 configuration, but we only get 17GB of usable HD Space.
3) Do all the Drives on a RAID 5 system need to be the same size?

Okay, here is the practical application for the questions. We have win2K server at work. It has 3 SCSI 9GB drives in a RAID configuration. The drives appear as 2 HD's, one of 4GB and one of 13GB. We are quickly using up this space, and need more space. The machine itself can actually hold one more drive. Do I need to purchase a 9GB drive or can I purchase a larger drive?

Also if someone could tell me the difference between Ultra 3 SCSI and Ultra 320 SCSI? Does this factor in to my purchasing decision or not (all I currently know about the system is that it has a 68pin SCSI drive in it, I know nothing about the Ultra 3/320 spec of the drives, or what this even means.

Also, on a side note, in general it seems that workstations, which use IDE drives, have more space than our server. This just seems backwards to me. I would think that a server should have the largest HD. In general do servers usually have SCSI Raid drives? If so, do they usually have drives smaller than that of individual workstations (which now days seem to have 40-80 GB standard) or do companies spend a lot of money putting multiple drives in their servers (my research shows me that SCSI drives run about 4 times as much as a same size IDE drive)? I work for a non-profit, so our technology is somewhat backwards...but I am somewhat disturbed that workstations have 40GB HD's while the shared server drive only has 13.

Peace,

O
B unce!

[utidjian]

Originally posted by NDBounce:
I am new to servers. My questions refer to a PC server, but I'm sure people here can help explain this to me:

1) What is RAID, and in particular RAID 5
2) Is there a formula to help determine how much drive space you will get off a RAID drive? ie Our office has a server with 3 9GB drives in a RAID 5 configuration, but we only get 17GB of usable HD Space.
3) Do all the Drives on a RAID 5 system need to be the same size?

Okay, here is the practical application for the questions. We have win2K server at work. It has 3 SCSI 9GB drives in a RAID configuration. The drives appear as 2 HD's, one of 4GB and one of 13GB. We are quickly using up this space, and need more space. The machine itself can actually hold one more drive. Do I need to purchase a 9GB drive or can I purchase a larger drive?

Also if someone could tell me the difference between Ultra 3 SCSI and Ultra 320 SCSI? Does this factor in to my purchasing decision or not (all I currently know about the system is that it has a 68pin SCSI drive in it, I know nothing about the Ultra 3/320 spec of the drives, or what this even means.

Also, on a side note, in general it seems that workstations, which use IDE drives, have more space than our server. This just seems backwards to me. I would think that a server should have the largest HD. In general do servers usually have SCSI Raid drives? If so, do they usually have drives smaller than that of individual workstations (which now days seem to have 40-80 GB standard) or do companies spend a lot of money putting multiple drives in their servers (my research shows me that SCSI drives run about 4 times as much as a same size IDE drive)? I work for a non-profit, so our technology is somewhat backwards...but I am somewhat disturbed that workstations have 40GB HD's while the shared server drive only has 13.

Peace,

O
B unce!

1)a) RAID == Redundant Array of Inexpensive Disks
b) RAID5 == a RAID array where all data AND all parity information is striped across all disks. IOW it gives you the benefits of striping AND mirroring.

2) The formula for RAID5 is (approximately):

Array_Size == (Number_of_disks - 1) * Size_of_disk

For example:

Given 3x9GB in a RAID5 array then the total useable size of the array is (again, approximately):
(3 - 1)*9GB = 18GB

Another example:

Given 9x3GB disks ( nine 3GB disks) in a RAID5 array then the total useable size of the array is (approximately):
(9 - 1)*3GB = 24GB

3) In hardware RAID the answer is yes, sort of*. There may be exceptions but I have never seen a hardware RAID controller that accepted disks of different size. Most hardware RAID controller manufacturers recommend that one use disks of the same size make and model in the array.

*sort of: One can use disks of different size with some controllers but the controller will automatically assume that all disks are as small as the smallest disk in the array.

You should get a 9G drive. If you get, say, an 18G drive and install it in the array you will lose the extra 9G of disk. Adding a 9G disk to the array will give you a total of about 27G in the array ((4-1)*9GB).
I would recommend that you get two new 9G disks. If one disk goes bad you will have a spare at hand. Also, 9G SCSI disks are pretty cheap these days.

Recently workstations have been shiiped with very large single disks (40, 60, 80, 100, and 120G IDE disks). Until recently servers usually contain several smaller, but RAIDed together SCSI disks. It is now possible to get IDE RAID controllers and put up to about 12 disks in a single array. Cases that hold 12 disks are harder to come by. Many newer, entry level, servers come with IDE-RAID.

For a small entry level file server or departmental server IDE-RAID is fine. It all depnds what you need to do and how much space your total shared files take up. In general, you need to determin what the needs are of your users and organization as a whole. If you are making lots of FinalCut Pro files then you are going to need a very big disk in the workstations and an even larger array in the server. For regular MS-Office files and a smallish database or two you will only need about 1G per regular user. It all depends.

Another thing to keep in mind is that RAID will give you high availability and higher reliability... it is, however, NOT a substitute for proper backups. In your limited budget you should determine the cost of complete data loss... and then compare that to the cost of a proper tape drive and set of tapes. Adding more disk space while increasing the total size of storage also increases the total amount of data you can lose if a disaster strikes.

I recommend that you spend some time with a consultant or user group member in your area planning out your strategy.

[Camelot]

I'm also willing to bet that the server is relatively old and is running Windows NT, right?

It's only in the last few years that hard drive sizes have grown dramatically. If the server is more than a few years old, 9GB was probably state of the art back then.

If you're running NT, NT will not boot off a partition larger than 4GB, and that's probably why the disks were partitioned into a 4GB and 13GB split.

As for IDE vs. SCSI, SCSI has a much higher throughput than IDE, although the recent IDE busses have narrowed the gap somewhat. IDE disks are much cheaper, but check what you're buying - many 'consumer' disks have limited runtime recommendations (e.g. "100 hours per month") which is completely inedaquate for a server.

SCSI has gone through multiple revisions over the years, with Ultra 320 being the latest incarnation and the current state-of-the-art.

However, if your machine is older it won't have a Ultra320 interface in it, and I don't know if you can even buy 9GB Ultra320 drives (the smallest I could find in a quick search was 18GB, most are 70, 80, or 160GB) - you're much more likely to have Ultra2 or maybe Ultra3 drives. Check the drive model number on the label and refer to the manufacturer's web site to be sure.

[Cipher13]

The drives are probably Ultra2. Ultra320 is MAJORLY expensive and major overkill for most applications - it's the fastest thing out there (it absolutely slaughters FireWire2, for reference. FW = 50MB/sec theoretical peak; FW800 = 100MB/sec theoretical peak; Ultra320 = 320MB/sec theoretical peak).

Get an ATA RAID card and go from there. The performance of modern ATA drives is plenty, unless you're doing some pretty hardcore stuff. What's the purpose of the server? ATA drives are cheaper, bigger (for the same price), etc. They're most definately not as hardy, though, so make sure the RAID array is indeed redundant (not just striped, for eg).

[NDBounce]

Wow,

Thank you all for the info.

The Server is running windows 2000 server. It is a Dell Poweredge 1300. It is the only server at my small (10 people) non-profit agency. I honestly don't know what is filling up a lot of the space. We do print a montly newsletter (6-8 pages) as well as an annual magazine type publication (about 150 pages). The graphics on those are probably the biggest files that we have. We also have a couple of databases that we use, but they are access databases, and I don't think any are bigger than 5MB, although I could be wrong on that. The one I use is about 2.5, and I just can't imagine that anyone has a bigger DB than me.

But I do thank you for you info. I do have a lot of questions regarding windows 2000 setup...can someone recommend a good place to go for info on that. I am getting varying opinions from various consultants, and I personally find our consultant to be very narrow in scope...and not willing to do things different...we had a major server crash which required Windows to be installed, and he really didn't want to restore web services for me, which as I do our web editing/development I need so that I don't have to test on the production environment.

Anyway, thank you for the help.

Peace,

O
B unce!

[MacOSR]

Originally posted by Cipher13:
The drives are probably Ultra2. Ultra320 is MAJORLY expensive and major overkill for most applications - it's the fastest thing out there (it absolutely slaughters FireWire2, for reference. FW = 50MB/sec theoretical peak; FW800 = 100MB/sec theoretical peak; Ultra320 = 320MB/sec theoretical peak).

Get an ATA RAID card and go from there. The performance of modern ATA drives is plenty, unless you're doing some pretty hardcore stuff. What's the purpose of the server? ATA drives are cheaper, bigger (for the same price), etc. They're most definately not as hardy, though, so make sure the RAID array is indeed redundant (not just striped, for eg).

Ultra 320 is not expensive any more! Dell is now shipping all (or nearly all) machines with 320 drives. I have also heard that 36G will soon be the smallest drive you can get as well.

BTW, Ultra 320 IS fast. I just setup a new server running Ultra 320 drives in a RAID 0+1 config. We are peaking at close to 600Mb/sec

[MacOSR]

Originally posted by NDBounce:
Wow,

Thank you all for the info.

The Server is running windows 2000 server. It is a Dell Poweredge 1300. It is the only server at my small (10 people) non-profit agency. I honestly don't know what is filling up a lot of the space. We do print a montly newsletter (6-8 pages) as well as an annual magazine type publication (about 150 pages). The graphics on those are probably the biggest files that we have. We also have a couple of databases that we use, but they are access databases, and I don't think any are bigger than 5MB, although I could be wrong on that. The one I use is about 2.5, and I just can't imagine that anyone has a bigger DB than me.

But I do thank you for you info. I do have a lot of questions regarding windows 2000 setup...can someone recommend a good place to go for info on that. I am getting varying opinions from various consultants, and I personally find our consultant to be very narrow in scope...and not willing to do things different...we had a major server crash which required Windows to be installed, and he really didn't want to restore web services for me, which as I do our web editing/development I need so that I don't have to test on the production environment.

Anyway, thank you for the help.

Peace,

O
B unce!

I would recommend disabling IIS on the file server unless absolutely necessary. Also, even with Windows 2000 it is still a good idea to do a 4Gb partition for Windows itself. All the file servers we have setup that are running Windows 2000 we have disabled EVERYTHING that was not necessary. The 1300 is a very good machine for a file server. You should also be able to find drives at a very reasonable price. Also, RAID 5 is the wise choice in your setup. Maybe use 3 36Gb (~72Gb useable) or 3 72Gb drives (~144Gb useable). Another thing to think about is that the 1300 will accept up to 4 1" hard drives so you could also add a "hot spare" drive to the RAID.

You may want to max the memory out if you start using the machine quite a bit. I *think* the limit on the 1300 was 1Gb.

I do have one question though...why did the server crash that hard?!? That does NOT sound good at all and SHOULD NOT happen. Do you have at least 20% of the hard drive free? If not you should!!!!! I can not stress this enough!

Microsoft publishes some very good books for W2K Server. If I was at the office I would give you a few titles but the best thing to do is make a trip to Borders and look through some books.

[MacOSR]

One more thing...make sure the BIOS is updated on the 1300 and the RAID card before you rebuild the machine!