Can we add lun to root disk for extending root filesystem.

[Nazaf Khan]

Hi,

Below are the details of my system space and I need to extend the /software/oracle space. I know you all will say why do we use database space in the vg00? For that I can say I really don't know as I got this setup like this here itself.

I need to ask is it possible to add a lun to this vg00 from external storage EVA to this internal disk i.e. boot disk. I feel it should not be done as it will generate lots of issue. But finally I need to wait for your recommandation. How can I extend the space any possibity?

--- Volume groups ---
VG Name /dev/vg00
VG Write Access read/write
VG Status available

/dev/vg00/lvol11 13312000 9679999 3409442 74% /software/oracle

PE Size (Mbytes) 8
Total PE 8680
Alloc PE 8602
Free PE 78

--- Physical volumes ---
PV Name /dev/dsk/c2t0d0
PV Status available
Total PE 4340
Free PE 39
Autoswitch On
Proactive Polling On

PV Name /dev/dsk/c3t2d0
PV Status available
Total PE 4340
Free PE 39
Autoswitch On
Proactive Polling On

--- Logical volumes ---
LV Name /dev/vg00/lvol11
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 13000
Current LE 1625
Allocated PE 3250
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation strict
IO Timeout (Seconds) default

[Torsten.]

I recommend to create a new LUN, create a new VG01, transfer the data to a new LVOL in VG01 and mount it to /software/oracle.

Doing this you have more space and a clean setup.

[Nazaf Khan]

Hi Torsten,

Thanks for the reply. I already have vg01 and vg02 also. I had already recommanded this to Database people and said the same. But they say there is no where writted in White paper or Docs of HP not to add Lun and extend the filesystem from lun to internal boot disk.

I will clear my query again. Can I add a lun to the internal boot disk and extend the filesystem?

LRUE-YFHP20_# bdf
Filesystem kbytes used avail %used Mounted on
/dev/vg00/lvol3 393216 52935 319047 14% /
/dev/vg00/lvol1 382933 40627 304012 12% /stand
/dev/vg00/lvol8 4194304 3214356 919166 78% /var
/dev/vg00/lvol9 2097152 1614 1964575 0% /var/adm/crash
/dev/vg00/lvol6 2097152 1350041 700837 66% /usr
/dev/vg00/lvol5 393216 2055 367550 1% /tmp
/dev/vg00/lvol11 13312000 9680068 3409370 74% /software/oracle
/dev/vg00/lvol7 3145728 1331069 1701820 44% /opt
/dev/vg00/lvol4 819200 643301 165208 80% /home
/dev/vg02/lvol6 2097152 512529 1485605 26% /data6
/dev/vg02/lvol5 6291456 5280512 947827 85% /data5
/dev/vg02/lvol4 14680064 12820514 1807432 88% /data4
/dev/vg02/lvol3 32014336 24265276 7507960 76% /data3
/dev/vg02/lvol2 19456000 9991335 8874158 53% /data2
/dev/vg02/lvol1 12021760 10398484 1572552 87% /data1
/dev/vg01/lvol1 34234368 29593546 4496126 87% /backup

[Torsten. · Accepted solution]

No problem.
But the LVOL is mirrored, so you need 2 new LUNs or unmirror the LVOL.

[Nazaf Khan]

Thnx Torsten again,

But one small doubt I have is if I add a lun from the EVA to this internal boot disk (internal disk in Server) Will it not create any issue. I mean will it not create issue when booted the system as vg00 is having 2 disk which is internal mirrored in system and 2 from external.

If there is no issue still then can this command be ok as I get the lun :

1.pvcreate -f
2.vgextend vg00
3.lvextend -L /dev/vg00/lvol11
4. # fsadm -F vxfs -b m /software/oracle <-- As online JFS is installed in it.
5. bdf /software/oracle

[Torsten.]

No issue expected in general.

But IMHO bad design.

[Matti_Kurkela]

Adding EVA LUNs to vg00 is *possible*, although mixing local and non-local disks in vg00 is very much not recommended.

Because the /dev/vg00/lvol11 is currently mirrored, the LVM would require two separate LUNs to extend the LV. This is because of the "strict" allocation rule. And you cannot mirror only a part of the LV: either the LV is completely mirrored, or not.

To plan for extension, it would be necessary to check the parameters of the VG, listed in the "vgdisplay vg00" output. Unfortunately, your output does not show that. What's the number of PVs accepted by vg00, and what's the number of extents allowed on them?

(If this is a standard HP-UX setup, the Max PE per PV parameter on vg00 is most likely 4340, restricting you to a LUN size of 4340 * 8 Mbytes = about 34,7 Gbytes, and to a small number of PVs. That would be inconvenient and rather silly, as modern SANs might present terabytes of storage.)

----

It would be much better to get a new LUN that is big enough to hold all of the new bigger /software/oracle and initialize it as a new VG.

Make sure that the PE size, MaxPE per PV, and MaxPV parameters of the new VG are large enough to support all predictable future growth of the filesystem. These parameters will be rather difficult (or even impossible, depending on HP-UX version) to change later.

Then create a new LV on the new VG and then mount it to some temporary location.

For example, let's call it /dev/vgoracle/lvol1 and mount it temporarily to /mnt/oracle.

Then, you could do this procedure:
1.) Shutdown Oracle.

2.) Copy all the data of /software/oracle to the new LV in its current temporary location, maintaining all file permissions and ownerships.

cd /software
tar cf - oracle | (cd /mnt; tar xpf -)

3.) Unmount /dev/vg00/lvol11 and /dev/vgoracle/lvol1.

4,) Mount /dev/vgoracle/lvol1 to /software/oracle. Edit /etc/fstab to make this mount persistent. Now all the files have exactly the same pathnames as before, only the storage has changed!

5.) Restart Oracle. Verify that it works exactly as before. If it doesn't, you can rollback simply by undoing step 4 and mounting /dev/vg00/lvol11 back to /software/oracle.

6.) If everything is OK, you can now lvremove /dev/vg00/lvol11.

MK

[Nazaf Khan]

Thnx for your great help. My all the doubts about it is cleared now u can close the Thread I had submitted the Points too ;)

[Torsten.]

>> u can close the Thread


YOU can do this.

Good luck!

[Nazaf Khan]

Thnx Again.