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Array Controller Upgrade Guide/Recommendations

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Jonathan Lopez_1
Occasional Visitor

Array Controller Upgrade Guide/Recommendations

How can I tell when I need to upgrade the array controller on my server? Specifically, what can I measure or monitor that tells me I need to upgrade my array controller, as opposed to my hard disks, etc?

And, how can I tell what array controller to upgrade to? Is there an "upgrade guide" somewhere out there to look at to tell me what controller to use for how many didks, or how much data, or how many users, or whatever criteria is recommended to use to determine the necessary controller?

For what it's worth, the system in question is a DL380 G1 w/ 18.2Gbx4 Ultra2 HDDs configured as 2 R5 logical disks, a 7.7Gb "C-drive" and a 43Gb "D-drive". D-drive is a file server and hosts a database, and lately users are complaining of slow access speed (Windows2000 PerfMon shows avg disk queue length about 6-7, and disk busy time often in the 100% range).
7 REPLIES
Jonathan Lopez_1
Occasional Visitor

Re: Array Controller Upgrade Guide/Recommendations

Although I appreciate the help, the links provided don't really seem to do much towards answering my questions. I don't need to know when to upgrade firmware roms, or how to do it. I'm more interested in knowing when to upgrade the actual hardware controller itself, to a higher-spec model.

Thanks, anyway.
Igor Karasik
Honored Contributor

Re: Array Controller Upgrade Guide/Recommendations

Jonathan ,
Do you use any SmartArray controller with your DL380? Which model?
Generally speaking adding cache memory to SmartArray controller will improve performance, replacing your Ultra2 drives to Ultra3/Ultra320 (if your SmartArray support it) will improve performance too.
There are some things you can do before SmartArray/SCSI drives/Server replace:
-Maybe database tuning is needed (e.g. adding indexes)
-you can create separate RAID-1 for OS - it will improve performance
-probably firmware update for SmartArray/SCSI drives will improve performance too (use firmware maintenance CD 7.40)

I don't know about general Array controller upgrade guide, but from your average disk queue length and % Disk Time it seems you really have problem with disk system, but anyway you need to check perfomance counters for CPU/memory/network as well.

See this link as well:
http://support.microsoft.com/default.aspx?scid=kb;en-us;310067
Jonathan Lopez_1
Occasional Visitor

Re: Array Controller Upgrade Guide/Recommendations

Hello, Igor. Thanks for the advice.

This server currently is using only the Integrated Smart Array Controller that comes with the DL380 G1 series server. It was adequate for about 4 years of use, until maybe 3-4 months ago.

Now that you mention it, just the above info alone seems to indicate perhaps the DB needs more maintenance than its getting, doesn't it? That is the responsibility of another team member, so I'm not quite sure what's going on there. I'll be sure to pass on the suggestion.

However, from a hardware point of view, I'm pretty sure a better Array controller will help alleviate the slowness. I'm betting more than upping the speed on the HDDs, but I'd like to be able to pinpoint for sure that this is the case. Thus, the request for help on how to show or measure when an array controller is a bottle-neck or not.

Also, even if I DID decide to upgrade the controller card, how can I accurately decide what level of performance is needed? Is there no algorithm or guide I can use to determine what class of array controller I should use, or is it just pick the model that ends in my lucky number?

Thanks!
Igor Karasik
Honored Contributor
Solution

Re: Array Controller Upgrade Guide/Recommendations

Jonathan,
there are many HP solution sizers exists:
http://h71019.www7.hp.com/activeanswers/Secure/71110-0-0-0-121.html
(HP passport required)
They don't talk about SmartArray controller specifically, HP typically talks about whole server.
Note: if you decide to buy and install new SmartArray controller you will need to upgrade your Ultra2 drives too - because you cannot get all performance benefits from new SmartArray controller while you use Ultra2 drives. So, instead new SmartArray controller and new SCSI drives you probably will decide to buy new server.
Anyway, try some steps to found where you have bottleneck BEFORE bying new hardware, especially if you write "It was adequate for about 4 years of use, until maybe 3-4 months ago"

You can find some useful information in SmartArray white pipers as well:
http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual〈=en&cc=us&docIndexId=179111&taskId=101&prodTypeId=329290&prodSeriesId=367226#2
Jonathan Lopez_1
Occasional Visitor

Re: Array Controller Upgrade Guide/Recommendations

Hi, Igor.

Thanks very much for all this info. It really helps!

I have been thinking and I have come up with the following method for determining whether an Array controller should be updated or not:

If you measure the "Total Bytes / Second" performance counter for a server, you could then compare this w/ the "Total Transfer Rate" throughput allowed for that array controller. If they are about the same, then the array controller is the bottleneck, and getting a better controller should allow more data transfer. What do you think?

To deterime whether or not it is the HDDs themselves vs. the array controller is a little more difficult. You could always do math and figure w/ an Array of 4 HDDs, you can get theoretical max transfer rate of 80MB/s (for Ultra2 SCSI) x 3 for read, but it will be slower for writes. Of course, this is only theoretical, as we all know that no HDD gives actual data transfer up to the rated speed.

I'm curious, what do you think of this methodology? My only problem is that I'm not sure if the "Disk Bytes/s" is the correct counter to use, or not, as our server reports a much larger value than I'd have expected.

Also, I am curious about one more thing for the array controllers, would you know: The Integrated controller supports 2 channels, 80MB/s each. How can we determine whether we are using 1 ch or 2 ch? I can not see this specified in any configuration utility (I see "4 drives attached to Port 2", but is "Port 2" = "Channel 2"??)

Thanks!
Igor Karasik
Honored Contributor

Re: Array Controller Upgrade Guide/Recommendations

Jonathan,
First, I want to say I am not performance expert (I am more "novice"), so take all I am write under suspicion.

I have some doubt about your methodology.
I think Disk Bytes/sec counter is not accurate especially when we use hardware RAID, Average PhysicalDisk counters is more suitable. In our organization we measure disk read/write latencies (from PhysicalDisk-avg. disk sec/write/read counters). We set our monitoring software (MOM) to send alerts when disk write/read latencies is greater than 20 milliseconds.
I think second weakness in your methodology is fact what SmartArray throughput and Ultra2 transfer rate is only theoretical values..

I think with performance monitoring you always need to compare current performance with past baselines. Do you have performance logs for this server for 4 months before when server performance was good? Maybe 4 months before disk performance counters were same and your problem now doesn't relate to disk subsystem.

Regarding SmartArray channels: I think port 2 is channel 2, but it is really doesn't matter because AFAIK you cannot use both channels on DL380 G1.

If you use HP Insight manager you can try to use
"ProLiant Essentials Performance Management Pack"
http://h18013.www1.hp.com/products/servers/proliantessentials/valuepack/pmp/index.html
to determine hardware bottlenecks

I hope another peoples will write more suggestions.