Optimal disk configuration

[user001]

Hi All,

I have an rx2600 and was curious what the optimal root disk configuration would be.

It has 3 slots.

I need to run mirror ux.

If i put a disk in 0 and 1 and mirror would that be better than.

Mirroring 3 disks and trying to share the load?

Thank you.

[Patrick Wallek]

First, does your RX2600 have a raid controller built in?  If so, use it for hardware level mirroring.

If it doesn't I would use 2 disks in slots 0 and 1 and mirror them. You could have a disk in slot 2 and have it be a spare.

[Torsten. · Accepted solution]

If you don't use the external SCSI connector, it could make sense to use the upper and lower disk slot.

The lower 2 slots are on the same bus, the upper slot and the external is the same bus.

[user001]

I think you are correct and this is what i thought as well.

0 and 2 would be optimal because of the bus configuration.

no it doesn't have a raid controller just using mirror ux.

why people use mirror ux instead of an actual raid card is beyond me, its never going to be as good right? i mean what are the benefits there will always be overhead with a software mirror?

thanks guys.

[Torsten.]

In the beginning there was no hardware RAID possible for the server internal disks, so LVM mirroring was the only choice.
Later (with the rp5400 server for example) there was the RAID 4si card, but IMHO LVM was much more reliable.
Nowadays you have smartarrays for the current servers, they are reliable and much more "comfortable". Try to replace a SAS internal disk mirrored by LVM running 11.31 - what a pain!

IMHO there is almost no overhead with LVM mirroring - you should not see a difference in performance.

[user001]

Hi Torsten,

I'm new to HPUX, nice explaination and history.

I was just looking at the rx2800 and noticed it had a raid card as well.

Agreed it is a pain to replace an lvm mirrored disk.

I might have to research lvm mirroring a bit more on a busy server, i'm curious about overheads and figures now. In my head i've always considered it to be enough overhead that it would be easily measured and compared against a physical raid mirror.

Cheers for the info.