RAID-5 on rp5430 server (HP_UX 11.0)

[Oleg Mercader-Kashin]

I have an HP9000/800/L1500-5x (rp5400 server) that has only 4 disk slots. Now we have one 18GB disk for system and 2x72GB mirror for an application.

We want to install +72GB disk and configure 3x72GB RAID5 for an apllication space but my salesman tells me that it's impossible (?!) and only a 2x72GB + 2x72GB configuration is possible.
Somebody know if that is true and why?

Thx you for your cooperation. It is appreciated.

[Jeff Schussele]

Hi Oleg,

L-class systems do not support RAID, of any type, on the internal disks. They can only be JBOD. You would need an external device that does support RAID to do this.

Rgds,
Jeff

[Thayanidhi]

Hi,

The internal disks are connected standard SCSI adapter.
RAID is not possible. All disks are accesible as standard
independent disks only.

Lately for some L-class systems there is a add on adapter(slot 3),
which can be installed and move SCSI connectors, which
will provide RAID capability.

Not sure on the above statement.

TT

[Joshua Scott]

There's no Hardware RAID available for the rp5400 or any of the rp series, I beleive.

You can do software mirroring (mirrordisk/UX)

As long as you get 4-72GB drives, mirrodisk would give you the 144GB that you are looking for and would give about 5x the performance of a RAID5 group.

I beleive that you can also purchase Software (Veritas) that provides RAID-5. Mirrordisk is much cheaper and RAID-1 is much faster.

[Oleg Mercader-Kashin]

Incredible! ... neither LVM nor JFS? I have its both:

LVM File System Configuration

This system is configured with Logical Volume Manager (LVM) file systems.
Refer to the File System layout section for information on the LVM layout.


JFS File System Configuration

This system is configured with a Journaled File System (referred to
as either JFS or VXFS). Refer to the File System layout section for
information on JFS/VXFS file systems.

[Leif Halvarsson_2]

Hi,
There is 3-party products (Veritas Volume Manager) which supports software RAID but I doubt if it is worth the money. A better (faster and perhaps cheaper) solution is an external hardware RAID, there is several vendors on the market.

[Bill Hassell]

LVM is a software method to divide the disks into sections (logical volumes) which can then be used as raw disk space, swap space or mountable filesystems.

VxFS (short for Veritas File System) or JFS (Journaled File System) mean the same thing: it is a directory and file manager.

Neither have anything to do with RAID levels. To be exact, LVM does have the ability to stripe data across multiple disk using software extents. The optional Mirror/UX product can be used to mirror up to 3 disks. But RAID-5 is not possible without a special controller. All HP-UX servers have a simple SCSI controller for internal disks. While Veritas Volume Manager (VxVM) offers a software-based RAID-5, it is not easily managed and uses a large amount of CPU time for computing parity information druing writes.

You need to look at an external disk array for RAID5 capability.

[Saurav_1]

Hi,

RAID5 is not possible. Rather RAID 0 kind of setup can be achieved using simple LVM commands among 3*72 GB Hdd. This is called stripping. In this if one of ur disk fails ur full data is lost. If U have MirrorDisk/UX software. U can implement stripping and mirroring together. but for that U have to have 4*72 GB hdd.

Saurav

[Oleg Mercader-Kashin]

OK, thx a lot, now I understand better how a LVM works.