MIRROR-UX & PV LINKS

[Christhian Chamba]

Hi,
Can you help me with the following question:

Actually I have 1 HP9000 rp7420 connected to 2 Storages by means of DAS.

I have 2 connections for the first and use PV Links and no multipath software, for the seccond I have only 1 connection.

I have MIRRUX-UX between a 1 LUN of the first storage and 1 LUN of the seccond storage.

I need remove the mirror for the first Storage and add a LUN of the new Storage in Mirror.

Do you think that I have any kind of problem because I have PV Links???...

Thanks...

[Michal Kapalka (mikap)]

hi,

no.

mikap

[Christhian Chamba]

Hi Michal,

Thank you for your reply... I mention to you that the server has installed Sysbase and use RAW DEVICE???...

Do you thing that I have ant kind of problems???...

[TTr]

> ...Sybase and use RAW DEVICE???...

Are the sybase raw devices on logical volumes? For example in sybase do you use raw devices that look like /dev/vgXX/lvolYY? If you have these raw devices then it is still OK to move the mirrors around, no problem.

[Christhian Chamba]

Hi TTr,

Thanks for your help, I use RAW DEVICE on filesystems in this case I can remove the STORAGE with PV Links of the mirror without problems???...

Thanks,

[TTr]

> I use RAW DEVICE on filesystems

What exactly do you mean here? Do you have raw volumes, files or both? Inside sybase where you specify the data and log devices what do you have? logical volumes paths or file name paths?
You need to verify this inside the sybase databases.

[Christhian Chamba]

Hi TTr,

I explain you: I have a rp7420 connect by DAS to 2 Storage, I use MIRROR UX betwen a 1 LUN of the first and 1 LUN of the Second Storage. I need remove of the MIRROR UX the first STORAGE that use PVLINK add a new STORAGE and then use MIRROR UX betwen a 1 LUN of the second storage and 1 LUN of the new storage.

The rp7420 have SYBASE and use RAW DEVICE and FILE SYSTEMS for the RAW DEVICE use the following format: /vg01/rlvol01.

I need know when I remove the first storage of the MIRROR UX or when I add the LUN of the new Storage I kave any knid of problem with SYBASE???...

Thanks,

[TTr · Accepted solution]

As I said before you need to verify what is sybase using for its raw devices. In the sybase configuration file for the sybase databases you have "sybase devices". Check to see that these sybase devices are logical volumes. Most likely they are and sybase does not have a problem

With LVM mirroring you have logical volumes that are laid over two physical volumes. When you remove one disk from the mirror, the logical volume is still available. So if sybase is using logical volumes as raw devices there is no problem.

[Christhian Chamba]

Hi TTr,

I attach a file SYBASE.cfg...

Grettings,

[Christhian Chamba]

Hi TTr,

I attach a configuration for a database nts_areas...

Grettings,

[Christhian Chamba]

I can see that the RAW DEVICES are Logical Devices, in this case when I remove the first storage don't have any problem with Sybase???...It's correct this...

Thanks for your help...

[TTr]

That's right, they are all logical volumes so they will be there even when you remove one of the disk mirrors. As always, when you do critical system work like this, take a good backup and do it when the system is not busy.

[Christhian Chamba]

Hi TTr,

Thanks for your help, in this case I do the activity with the full backup of the database and with downtime of 1 hour for anything.

Grettings,

[TTr]

Verify that all the logical volumes are mirrored to the two disks in each volume group. Run "lvdisplay -v /dev/vgXX/lvolYY" and ensure that each logical extend LE has two physical extends PE one on each disk in the volume group. Do that for all the logical volumes that are used by sybase.

[Christhian Chamba]

Hi TTr,

All logical volumes that Sybase are used are in mirror in the 2 storages.

Thanks for your help...

[Christhian Chamba]

I finde the solution...