LH3 Performance

[Jon Watry]

Maybe i'm just expecting to much but my LH3's seem slow when copying data to them. One night I copied the same file to an LH3 and a PC and the PC was faster. What kind of tranfer rate shoould I get with the following setups. Also what is a good program to test the transfer rates on the hard drives so I can get some actual numbers. I tried HP's PAT and the transfer rate on the Sequential test was 12.22Mb/sec

Server 1
6x9gig 7200Rpm:(
Raid 5 using all 6 drives

server 2 is same but 18gig drives

[Jon Watry]

Also is is possible to upgrade the cache on the RAID controller?

[BR642007 · Accepted solution]

Jon,

An LH3 with 6 harddisks in RAID5 should be pretty fast.
Some things that can slow down the server are:
-stripsize on the RAID5 set: small stripesize (4k) gets worse performance than a large stripesize (64k)
- Transfer Speed on SCSI-channel: Boot to Ctrl-M (Express Tools) and check: Objects->Scsi Channel-> SCSI Transfer Rate=Ultra2.
If it's FAST (20MB/sec) or Ultra (40MB/sec) you should set it to Ultra2 (80MB/sec).
Only do this when your harddisks are also Ultra2 compatible.
If you're not sure about this, just let me know the productnumber of the disks...

Also check Objects->Logical Drive-> Properties the Write Policy, Read Policy and Cache Policy of the logical drive.
You can also see the Stripesize of the logical drive here.

The Netraid Cache is upgradable to 64MB max (p/n: D7132A).

Marco.

[Jon Watry]

I just checked my BDC(the 9gig array) and found out the transfer rate was set to FAST and I changed it to ultra-2. I ran HP's PAT again and the same test came out to 23.73Mb/sec this time.

below are the setting on the Logical Drive

Raid = 5
Size = 43385MB
StripeSize = 64KB
Write Policy = WRTHRU
Read Policy = ADAPTIVE
Cace Policy = CachedIO
Virtual Sizing = DISABLED
#Sripes = 6
Sate = OPTIMAL

Do you think the 64MB Cache upgrade would be worth it?

[CA744873]

What is the purpose of this machine?
If there is a LOT of disk I/O from multiple sources, then it can help. If there is not, or the bulk of the I/O goes to a single source, then the increased cache is unlikely to impact performance.

The best impact you can do is the raid level.

RAID 5 is a good balance between read/write.

RAID 0 is great read/write I/O but no redundancy

RAID 3 is great read, worse write access.

A RAID 50 would improve read access without degrading write access.

A RAID 30 would improve read access wile further degrading write access.

You might backup your data, and try a few RAID configs with testing for the best balance for your needs.

[Jon Watry]

One is my PDC which does DHCP, WINS, Print and has the home directorys for 2500 students and also contains about 2gigs of data that the differnt departments in the school share.

My BDC is home to more than 100 applications but the most used ones are the databases for the library and Eureka a carrer finder program and Microtype multimedia which is 200MB and almost 100MB of it is avi's. This server also contains about 8GB in the 200 staff directorys.

Both servers have 2gig fat partitions and the rest of the Raid is a single NTFS partition.

Also sometime this year we will be moving the attendance database over to one of these servers. Each school database is about 15-60MB and there are about 40 very active users with another 20 light users. Also with this move we will start using a web based version the softeware and it has the potential to be used by the whole school which is around 200users. I plan on putting this software on the BDC but should I put it on the PDC?

Also if there is anything at all that you would change on the servers above let me know. you will not ofend me since a company set the servers up about 2years before I took over this job.

Also do you defrag a RAID array?

Thanks

[Torben Hoeiby]

The fastest is when the blocking size on the volume (default 4k) you specify when formatting the volume, matches the stripe size of the netraid controller. I know - you might loose some capacity on that vol if you have many small files. But there is no such thing ad a free lunch.

Furthermore you cache policy could be set to write back. That would speed up writing. But be aware that the LH3 does not have battery backup on the netraid controller cache so data corruption is a potential risc in case of a powerfailure on a system without UPS. (this only applies to onboard and netraid 1 ctrls)

[Jon Watry]

Torben thanks for the info.

I plan on adding more disks to the BDC later this year and I will try a larger stripe size. This evening I will also change the setting on the raid controller.