Hard drives of rx1600

[nibble]

Guys, i have to replace the drive of my rx1600. the replacement drive that i have indicates that its hot-swappable:
PN: A9922A
Drive : 36GB hot-plug Ultra320 Low Voltage Differential (LVD) SCSI hard drive - 10,000 RPM, 3.5-inch form factor, 1.0-inch high

But what bothers me is this warning from the rx1600 manual:

HP Integrity rx1600 and rx1620 Servers - Installing Internal Hard Disk Drives
A hot-plug device may require interaction with the operating system before the device can be safely installed into the server. Verify that the operating system supports installing disk drives while the operating system is running. If the operating system does not support this feature, shut down the operating system before attempting this procedure. Failure to observe this caution will result in system failure.


Generally, is the drive of rx1600 hot-pluggable?

here's my machine model.

Product ID : ia64 hp server rx1600
Product Number : A9901A

running HP-UX B.11.23 64 bit

by the way, this is related to my posting:
http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1205094645909+28353475&threadId=1209758
I've replacd HP 9000 drives many times, but this is my first time to replace an rx1600 with a production system. we dont have support with hp so i have to do it myself.

AND the good news is, i was able to figure out that its not the PRIMARY drive that i have to replace. All i need now is to replace the secondary drive.

any help will be appreciated.

Thanks.

[Hein van den Heuvel · Accepted solution]

>> A hot-plug device may require interaction with the operating system before the device can be safely installed into the server.

That basically mean you should stop all IO to the drive and, if at all possible, dismount the disk for the OS. That's all.
You were going to do that anyway right?

That may mean stopping applications (fuser).
I may be tricky if you allocated swap space on the drive.

After dismount, yank, plug, scan.

Also, I would not deliberatly have High IO on the bus while plug & playing, like start a large file copy. It is supposed to work, but why not wait untill all is relatively quiet. You were going to do that anyway right?

Good luck! You'll need some, but not much. Mostly this works fine.

[TTr]

> Guys, i have to replace the drive of my rx1600. the replacement drive that i have indicates that its hot-swappable:

> Generally, is the drive of rx1600 hot-pluggable?

There is some difference between hot-pluggable and hot-swappable but that difference is not always emphasized. Hot-pluggable refers to the physical (eletrical/electronic) aspects of the devices and pretty much everything nowadays is hot swappable. (If you remember in the old K-series server if you hot-plugged a FWD drive most of the time you hung the bus).

But in addition to the hot plugging of the device, there is additional intervention needed to make the device operational again.

If the device as soon as is hot plugged, it is automatically integrated and used by the system the same way as the replaced device, it is refered to as hot swappable.

Example: disks in LVM mirrored pairs are hot pluggable. disks in internal and external RAID controllers are hot swappable.

> A hot-plug device may require interaction with the operating system...

So the question really is how is "the internal drive" set up? Is it part of an LVM mirrored pair, part of an internal RAID controller mirrored pair or single drive with the HP-UX on it?

That 's what the manual refers to when they mention "interaction with the OS" and "system failure" etc.

[nibble]

Guys, this is by the way a mirrored root drive.

[nibble]

TTr,

I have 2 drives in my rx1600. they are both configured in one VG with the OS on it and has been mirrored using ux/mirroring. the secondary drive is failing, have bad blocks on it, but it is currently attached and running fine. its being claimed in the ioscan.

[Hein van den Heuvel]

There is not such thing as secondary drive in a mirror set. Both are equally (un)important. The price and consequences of loosing either is exactly the same.

I suggested you read up on the process a little.

google: lvm mirror replace bad

Suggested read:
http://docs.hp.com/en/5991-1236/When_Good_Disks_Go_Bad.pdf

Good luck!
Hein.

[Mridul Shrivastava]

As mentioned in your previous post as well the follwing statement is self explanatory:

>> Installing Internal Hard Disk Drives
A hot-plug device may require interaction with the operating system before the device can be safely installed into the server. Verify that the operating system supports installing disk drives while the operating system is running.

This means that you should have LVM OLR patches to replace the drive online. If you dont then u have to do lvredure then vgreduce so there wont be any I/O going on that disk so this can be done online in that case. So in nutshell this can be done online using the following two scenarios:

1. If LVM OLR patches are there just execute pvhcange -a n and replace and followed by pvchange -a y then other steps to restore the vg conf , boot info etc.

2. Without LVM OLR.. need to break the mirror and replace the disk and re-mirror the disk.

Hope this clear up your doubts.

[nibble]

Thanks everyone.