October 13, 2003 at 8:37 am
I am about to purchase a new Server for our Database Server, SQL Server 2000 with 16 Users and a 4Gig Database. The configuration is about clear, it's going to be a Compaq Proliant with 2G Ram, all components pretty much standard, BUT I have a hard time finding out whether an investment in 15K rpm Disks instead of 10K Disks makes sense.
There is a roughly one-hour job on the server which should be accelerated as much as possible. While this job runs, the CPU shows 10-70 % usage in task mgr. This makes me think the disks are the bottleneck. However, we already have 10K rpm disks (18GB). So if the new server had 10K rpm disks, too, would it run at roughly the same speed ? It could not make use of a faster CPU, could it?
What should I buy ?
October 13, 2003 at 10:43 am
Whats your disk utilization and queueing look like? Sometimes raw speed counts. How many drives are you going to have in what configuration?
Andy
October 13, 2003 at 8:29 pm
Hi
16 users hey, DSS or OLTP, what sort of read/write activity are you looking at. To be honest, unless is really intense access and its a large db, you wont have a prob with the 2gb ram etc. The 10k drives should be ok, with the extra dosh use it to buy 2 or more, the more spindles in a raid-5 array or a raid-1 and raid-5 config will be fine.
Cheers
Ck
Chris Kempster
Author of "SQL Server 2k for the Oracle DBA"
Chris Kempster
www.chriskempster.com
Author of "SQL Server Backup, Recovery & Troubleshooting"
Author of "SQL Server 2k for the Oracle DBA"
October 13, 2003 at 10:12 pm
Whether you go for 15k discs of 10k like has already been said depends on teh hard drive load. I would probably go for the 15k drives, as databases nearly always tend to be disc intensive. Also, Raid 1 would be the better choice for the disc subsystems... Raid 5 would impose too much overhead (although small) in the calculation of the checksums. If the disc drives arent the problem, then spend the extra money on more memory
Nigel H.
Infrastructure
Lockheed Martin Australia
October 13, 2003 at 10:29 pm
We have a large number of Compaq servers in our organization and found a few interesting items related to Compaq server. If your disk util. is high look to see what percentage is write related. Write performance often suffers often the raid 5 config.
Write Bound Issues:
1. Compaq in the infinite wisdom provides onboard 5i Raid controller but does not include a write-back cache enabler. This is a separate purchase item and most vendors over look the module < $500. But can increase the write performance 30-50%
2. The new Compaq U320 raid controllers have the same problem the write cache enabler is a separate product almost always overlooked and again a minor cost < $500
Read Bound Issues:
1. More spindles are the fastest improvement without a large cost.
2. Replace the 10K with 15K can make a noticeable improvement but don’t count on more that about 20-30%. But you must replace all drives in the Raid array.
Good Luck,
Sean Breyer
October 14, 2003 at 2:25 am
And just summarising all what have been said I would say that for SQL Server performance what you need (in this order) Processor speed, memory and then disk.
Normally if you have enough RAM then you cache hit ratio should be around 100%.
In this case the disk is not playing an enormous role.
As you've daid you DB size will be around 4GB and you are planning to have 2GB RAM.
In this case you can take the 10K disks. Even tough the 15K will be faster at some extent.
What you have to consider is the type of your job you want to speed up.
What is that job doing?
Reads the whole DB sequentially => You need the fastest disks possible
Reads a chunk of data and then works on => You need memory and processor
4GB for the DB size and 16 users are really not so big so I think you won't experience any preformance issue by using the 10K disk.
Bye
Gabor
Bye
Gabor
October 15, 2003 at 7:47 am
Get the cheaper disks and use the money to buy a SCSI attached disk cage with 17 bays. Load it up with smaller disks to give you more spindles.
October 16, 2003 at 12:50 am
Thank you all for your help. I have ordered the 10K Disks and asked my dealer for info on the write-cache-enabler. Seems to make sense to invest <500$ since the critical 1-hour-job includes a lot of writing.
Kay
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