VxVM

[Brad Kozak]

We currently have an N Class server with LVM, MirrorUX, and OnlineJFS. We're specifying out a new server (rp3400, EVA3000), and our vendor suggested replacing all 3 of those products with the full version of VxVM -- they also mentioned that the EVA came with SecurePath. I'm completely in the dark regarding VxVM and just looking for some insight. I guess the questions are:

1) Will we be able to mirror the internal (OS disks)?
2) Will we be able to stripe and mirror the disks in the EVA?
3) What's up with SecurePath and how does it work with VxVM?, or does it do RAID 1/0 within the EVA so we wouldn't need to have VxVM manage the disks in there? If SecurePath does the RAIDing within the EVA, then why would I need to purchase the full version of VxVM? -- or is it simply an option? (i.e. they'll both work) Which one is better in that case?

TIA,

Brad.

[RAC_1]

1. Yes.
2. Yes. It offers much more here. You change the FS layout on the fly.
3. Yes. Secure path works with VxVM. You can also drop out secure path and use vxdmp. It offers same features as that of secure path. You can save some money here.

VxVM offers software raid also. But when storage can do it at hardware level, why do it at OS level??

[Duncan Edmonstone · Accepted solution]

Brad,

I have to say I don't really understand what extra feature your vendor is pushing you towards VxVM for - if your storage is all on the EVA then why would you need an adavanced volume management tool like VxVM? Unless you need more advanced features like volume replication,

SecurePath doesn't do RAID - it does multi-pathing and you DO need it on HPUX to access the EVA. If all you're going to mirror is your boot disks the MirrorDisk will do the job for you fine, and is simpler and cheaper than the full version of VxVM.

With regards to Online JFS - that is just the veritas filesystem anyway (VxFS)

HTH

Duncan

[Pete Randall]

Brad,

Let your EVA hardware take care of the mirroring and striping. Mirroring, whether LVM or VxVM is used primarily for your internal root disks and it's primarily a choice of which you are more comfortable with: LVM/MirrorDisk or VxVM.


Pete

[Brad Kozak]

RAC, Duncan and Pete. Thank you for your time and expertise. It is much appreciated.

Brad.

[Alzhy]

You don't need full VxVM if you will be using EVA storage with your HP-UX servers. However, you will still need path protection offered by SecurePath (if you're concerned with path failures to your array). You will also need MirrorDisk/UX at least for your local/non-EVA OS/boot disks if you want protection for your OS. But if you will be using EVA bootdisks, then you will not need MirrorDisk/UX anymore has your EVA bootdisks/Luns will already be protected anyway. However, for full boot support on your EVA LUNs - you will need SecurePath and stick with LVM for your OS disks.


And to correct some responses posted and as an FYI:

1. Veritas DMP with the Full License (path protection) CANNOT replace SecurePath as DMP simply is not supported on the EVAs.

2. EVA OS boot is only fully supported if you've SecurePath 3.0D or later and use LVM.

3. SecurePath 3.0C and later + VxVM (Lite/Base or Full) is fully supported but not on your OS disks -- which means, you will need to stick with LVM on your vg00 or root disks.

In your case, I'd say I will still insist SecurePath purchase - boot off your EVA's so you avoid purchasing MirrorDisk and use LVM for your OS storage. For your non-root stoeage, I will still prefer you use VxVM Lite (the version bundled free) since you will not have any need for mirroring or DMP or online relayout features. BaseVxVM/Lite still offer a number of advantages over LVM..

[RolandH]

1. As I know the root mirror is already possible with the VxVM basic product. But if you want mirror other LV/VG you need the full product.

2. YES

3. SecurePath does not does not "RAIDing"

The only reason I know to use VxVM is when you want use more than 256 VG with a host.

Roland

[Alzhy]

RolandH,

VxVM "rootability" - meaning placing your root OS disks under VxVM control has been supported since SEP 2002. But there are certain combinations that are not fully supported -- one is the EVA with SecurePath. You can use VxVM to boot off EVA disks (encapulate is the right term I think) with SecurePath BUT it will not be fully supported.

[RolandH]

THX Nelson - Good to know that the base product form VxVM is not supported with secure path.

Roland

[Alzhy]

Correction: It is supported but not on EVA / SecurePath root disks -- which need to remain as LVM Managed. You can however drop purchaing MirrorDisk since you no longer need to mirror your OS disk if you'll be using EVA LUNs.