Filesystems, Disks and Memory

Hi

Today I got a good question. One particular tester came to me and asked if it is the disk that is holding back our 2way HP 9000/A500 system.
I suddenly realized that I had no idea whether the output of iostat meant that the disk was already nearing its limits or not.
root@-------:/# iostat 10 5

device bps sps msps

c1t15d0 15 4.2 1.0
c3t15d0 0 0.0 1.0

So How Much Is Too Much?
I did not really find anything on the net about it.

Thanks

Doubtful - I ran the same command on a dev server (HP) and got close to the same results.

Try looking further into what is happening on the server. Look at cpu usage, error messages (if it logs messages showing that there is something wrong with the disk {ie. multi bad reads}, swap usage, if it's happening all the time, some of the time, ...

Investigate - throwing out one set of numbers won't get an answer of "That's the problem". These types of problems need much more detail for folks to answer with any kind of certainty.

The output from two of the disks iostat ran against for me:
c1t6d0 75 8.2 1.0
c1t5d0 28 5.5 1.0

The disks exist to serve processes. When you get to "too much" you will have processes waiting for disk i/o. To see how close you are that threshold on an HP system, I suggest that you use HP's glance product. If you have a disk bottleneck, it will tell you so. It's an amazing product.

Perderabo, do you know if Glance comes only with 9000 series or is it on all HP servers?

I have the uneasy feeling that this is a trick question.

Here is HP's page on Glance. I would be amazed if it runs on all HP servers, especially this soon after buying Compaq. I think that its availability is based on OS and I know it's available on HP-UX for sure. I think it's also available for MPE. But HP has also sold boxes that run Microsoft OS's. I don't know about them. Is OpenVMS a HP Operating System at this point? I guess so, but I don't think Glance runs on it yet.

HP has Itanium boxes that can triple boot HP-UX, Linux, and Windows. I think that you can run glance only with HP-UX.

So it's not the box, it's the OS.

And the "comes with" clause of your question is another problem. A trial version is bundled with HP-UX. For that matter, I believe that trial versions are available for download. But you're supposed to try it and if you like it, you then buy it.

No tricks - just was wondering - the man page shows the following and after looking at the utility I was wondering if it was only for 9000 systems:

Glance aids performance problem resolution on all HP 9000 series systems