RAID Levels

[tglake]

What spec server?

I'm about to buy a new Server for the first time.

It will support about 10 client PCs (XP Pro) over 100mbit LAN.
We are running MS Office and the key app is a set of MS Access dbs - the largest is 30mb.

I currently have performance problems with the databases, which can take 10-20 seconds to open a form (they are currently served off a peer PC running XP Pro)

I need advice on what spec Server to get.
I'm looking a dual Xeon 2.8Mhz, 1 Gb memory, SCSI hard drives.

3 key questions:

1. what RAID level should I use for performance - I have budget constraints here
2. what are the key items to spend on to enhance db performance.
3. will gigabit networking help too?

Thanks in advance

 

[HoLoCroN]

tglake ,

In order to get good database performance out of your server/workstation setup you need to have a few things decided prior to making the purchase. (You asked all the right questions)

Access is the Database (Frontend) are you using a backend Database application (SQL, Oracle) or is it a centralized Access DB with forms at the workstation level to update and manage the DB?


A couple of things,

Type of network cards:
Since you will be working with DB applications you might want to go for the Gbps network plan, the price difference is not that much and you increase your bandwith between server and workstations.

RAID Configuration:
I recommend using a combination of RAID configurations on your server (You can have multiple RAID configurations on one server). This is one of the crucial elements in performance and you really shouldn't short-change here. It is basically three RAID configurations.

1) You setup two hard drives on a RAID 1 - Disk Mirroring configuration that will house your System (Windows OS Partition). Mirroring these volumes ensures that you'll be able to boot the server in the case of a single drive failure.

2) You setup a second RAID configuration using RAID 5 - three drives should suffice, this will be the partition used to house your database. RAID 5 is basically an enhanced version or RAID 1, with the key addition of fault tolerance. Fault tolerance ensures that the failure of a single drive won't bring down the entire drive set. Instead the set continues to function with disk operations directed at the remaining volumes in the set.

3) Finally, Set one drive as a spare, just in case any of the drives in the RAID 1 or 5 sets fail, the spare will immediately take the place of the damaged drive and automatically regenerate the drive set.

With this RAID 1, RAID 5, spare drive configuration, you are basically simplifying your troubleshooting in the case of a drive failure (IT HAPPENS! Trust me, I just had a drive on my PDC crash). All you have to do to fix it is take out the faulty drive and insert a new one and you are done! the RAID controller does the rest of the work.

To sum it up, you need 6 SCSI drives and like I said, this is a vital element in your new configuration. You now have a single point of failure (Server) and you really have to make sure that you have redundancy now.

By applying these configurations, you will be optamizing your system for database use and have a redundant system.

If you have any other questions let us know.

 

[tglake]

thanks

6 SCSI drives is looking quite pricey. If I wanted to cut that back to save cost, what you recommend. Just RAID5 with data and operating system in the same place?

How important are the processors or memory going to be?

At the moment the db is all MS Access. Will SQL Server make a big difference?

 

[HoLoCroN]

The system settings you posted earlier is enough for now and should be able to handle any growth in the near future.

You need at least 3 drives for RAID 5 to work.

You don't want to put your system and data on the same volumes because if anything happens, you're completely sunk. It will take hours if not days just to get back operational, and there is no guarantee the DB will stay intact.

You can cut it down to five drives and eliminate the spare drive but if you are going to have a functioning server with the fault tolerance you need, this is the minimum configuration possible. I know it is pricey, I have $30,000 servers and those are the cheap ones, but if this is your business and it relies on the technology, you will loose much more money in the event of a faulty drive since you will have to pay for the replacement parts, time spent reparing the failure, salaries of the rest of the employees and downtime of the business.

If you can manage to get the five drives, it will save you money in the long run, give you peace of mind (and its a good tax write off).

 

[ChaosBlizzard]

Re: What spec server?

I'm about to buy a new Server for the first time.

It will support about 10 client PCs (XP Pro) over 100mbit LAN.
We are running MS Office and the key app is a set of MS Access dbs - the largest is 30mb.

I currently have performance problems with the databases, which can take 10-20 seconds to open a form (they are currently served off a peer PC running XP Pro)

I need advice on what spec Server to get.
I'm looking a dual Xeon 2.8Mhz, 1 Gb memory, SCSI hard drives.

3 key questions:

1. what RAID level should I use for performance - I have budget constraints here
2. what are the key items to spend on to enhance db performance.
3. will gigabit networking help too?

Thanks in advance

You might find this site helpful:
http://www.acnc.com/04_01_00.html

It will give you the pros and cons of certain raid levels....

 

[tglake]

thanks folks - very useful.

 

[tglake]

OK
Dell can do a good price for my budget with 4 SCSI drives. That may be too few, but I'd like to see if that will work.

If I just set up RAID 5 for 4 drives, will I be compromising much or is that going to work?