Expanding lvol mount point

[Mike Tufariello]

I have mount point; /dev/vgprod1/lvol8 146800640 129128328 17535008 88% /amiarch, that needs more space assigned to it.

I am running on a RP7420, OS 11.11i, cabled to an EVA5000.

Not sure is I have JFS.
/amiarch VxFS /dev/vgprod1/lvol8

When I check the mount point in SAM I get;

Logical Volume: lvol8
Volume Group: vgprod1
Space Available in Volume Group (Mbytes): 27540 --------
Current Logical Volume Size (Mbytes): 143360

So does this really mean that I have 27.5 GB in VGPROD1 available to add to the mount point?

I've read other threads and saw that ultimately SAM was used in the single user mode to expand the mount point. The mount point I am working with is very rarely in use. So do I really have to drop to single users mode to increase the size. Or can I perform this during normal operations?

Also I am hooked into an EVA5000 and all the disk are in a RAID 1 configuration. Should I have any concern about this or will SAM take care of the RAID?

Here is my vgdisplay;

vgdisplay -v /dev/vgprod1
--- Volume groups ---
VG Name /dev/vgprod1
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 11
Open LV 11
Max PV 16
Cur PV 9
Act PV 9
Max PE per PV 12799
VGDA 18
PE Size (Mbytes) 4
Total PE 115173
Alloc PE 108288
Free PE 6885
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgprod1/lvol1
LV Status available/syncd
LV Size (Mbytes) 122880
Current LE 30720
Allocated PE 30720
Used PV 5

LV Name /dev/vgprod1/lvol2
LV Status available/syncd
LV Size (Mbytes) 10240
Current LE 2560
Allocated PE 2560
Used PV 1

LV Name /dev/vgprod1/lvol3
LV Status available/syncd
LV Size (Mbytes) 20480
Current LE 5120
Allocated PE 5120
Used PV 1

LV Name /dev/vgprod1/lvol4
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 256
Allocated PE 256
Used PV 1

LV Name /dev/vgprod1/lvol5
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 256
Allocated PE 256
Used PV 1

LV Name /dev/vgprod1/lvol6
LV Status available/syncd
LV Size (Mbytes) 1024
Current LE 256
Allocated PE 256
Used PV 1

LV Name /dev/vgprod1/lvol7
LV Status available/syncd
LV Size (Mbytes) 71680
Current LE 17920
Allocated PE 17920
Used PV 3

LV Name /dev/vgprod1/lvol8
LV Status available/syncd
LV Size (Mbytes) 143360
Current LE 35840
Allocated PE 35840
Used PV 4

LV Name /dev/vgprod1/lvol9
LV Status available/syncd
LV Size (Mbytes) 20480
Current LE 5120
Allocated PE 5120
Used PV 1

LV Name /dev/vgprod1/lvol10
LV Status available/syncd
LV Size (Mbytes) 20480
Current LE 5120
Allocated PE 5120
Used PV 1

LV Name /dev/vgprod1/lvol11
LV Status available/syncd
LV Size (Mbytes) 20480
Current LE 5120
Allocated PE 5120
Used PV 1


--- Physical volumes ---
PV Name /dev/dsk/c22t0d0
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t0d1
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t0d2
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t0d3
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t0d4
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t0d5
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t0d6
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t0d7
PV Status available
Total PE 12797
Free PE 0
Autoswitch On

PV Name /dev/dsk/c22t1d0
PV Status available
Total PE 12797
Free PE 6885
Autoswitch On



Thanks in advance for any help you or anyone else can offer.

[Victor BERRIDGE]

Hi,
You have 27GB of spare yes - for this volume group whis has 11 lvols, so think twice...
I would add maybe 10GB and keep the rest to stay safe...
Keep also in mind, you have 9 PV allocated - your maximum is 16...

There is no need to use sam in single user if you are sure no one is using that file system at the time you wish to extend it and it may be the safest alternative since you are not sure of having online-JFS, which if it the case will fail if someone is using that file system...
There nothing stopping you to check before with fuser...

All the best
Victor

[Pete Randall]

Mike,

It is not necessary to go to single user mode as long as the File System can be unmounted. Go ahead and try it with SAM - it will tell you if it can't be unmounted.


Pete

[A. Clay Stephenson]

It means that you have ~27 GiB of unassigned space in the Volume Group that can be assigned to any existing Logical Volume in the VG ior used to create new LVOL(s) in the VG.

Do a "swlist | grep JFS" to see if you have the optional OnlineJFS product installed. If so then you can extend the LVOL and increase the size of the filesystem "on the fly" while the filesystem is mounted and in use. You can actually do all of this within SAM -> Disks and Filesystems -> Logical Volumes -> Actions -> Increase Size (This will grow the LVOL and extend the filesystem).

or you can do via the command line using lvextend and fsadm. Man lvextend and fsadm_vxfs for details.

[Ninad_1]

You can check if you have got Online JFS by
swlist | grep -i online

Yes you have got 27 Gb in your VG which can be used for extending your lvol8
You do not need to goto single user mode to extend the logical volume unless the lvol is related to /usr, /var, /tmp, /var/tmp
You can unmount your filesystem if its possible [ assuming you have a filesys on lvol8 ]
After unmounting use lvextend to extend the size of logical volume and then use extendfs to extend the filesystem to make use of the extended logical volume. and then mount the filesystem again.
If you have Online JFS you can do this online without unmounting the filesystem. using fsadm after using lvextend.
see man lvextend and man extendfs.

Regards,
Ninad

[James R. Ferguson]

Hi Mike:

SAM isn't lying. If you look at the 'vgdisplay' output for the volume group in question you will see each LVM physical extent is 4MB in size. You have 6,885 of them free, so 4*6885 = 27,540 MB.

If you don't have Online JFS then you must be able to let SAM unmount the filesystem in order to change its size. SAM will deduce this for you and act (or not act) accordingly.

I presume that this is not your boot disk since by convention that's named 'vg00'. Given that you can quiesce all processes using the filesystem (in the logical volume) that you want to extend, then should it need to be unmounted, it will be and the resize will be performed.

If you have Online JFS, no unmount is necessary and therefore no processes using the filesytem need to be terminated for the unmount to occur. You can see if you have Online JFS by looking for it thusly:

# swlist -l fileset|grep -i OnlineJFS

If you were extending a filesystem belonging to vg00, and if you didn't have OnlineJFS, then you would boot up into single-user mode where only root is mounted to perform the filesystem resizing. This would be the course to take to avoid having to kill processes utilizing the filesystem that you were trying to unmount and resize.

Regards!

...JRF...

[Darrel Louis]

Hi,

Yes you've something like 27 Gb available (Free PE * PE Size => 6885 * 4 Mb)

You can check with "swlist -l fileset|grep -i jfs" to see if you have Online JFS installed.

As victor mentioned don't used it all.

Darrel

[NMory]

Mike:

You can check if you have OnlineJFS installed by doing:

# swlist -l product |grep -i OnlineJFS

If you have space available in your volume group, definitely you can use that extra space and assign it to your lvol.

You can do the expansion of the logical volume with the command line, it's better. If you have Online JFS you can do the whole procedure with the file system mounted on that lvol and there is no need to boot into single user mode... If the lvol is mirrored via Hardware the EVA shoould take care of it when you do the extension...If it's SW raid then is recommended to reduce the mirror extend the lvol and then recreate the mirror...

For cookbooks on how to these procedures, go to the following website:

http://www1.itrc.hp.com/service/iv/node.do?node=prodITRC%2FWW_Start%2FN1%7C20%7C3%7C1%7C2

Regards,

LN

[Mike Tufariello]

Victor,

Why only assign 10 of the 15 GB to the lvol?
Will the number of PV increase from 9 to something else after I add the 10 or more GB? Can I predict how many PVs?

Thanks,

[Mike Tufariello]

Hello all,

To tell if I have online JFS I ran all the commands you suggested and here are the results;

swlist | grep JFS gives me nothing

swlist | grep -i online gives me
OnlineDiag B.11.11.14.15 HPUX 11.11 Support Tools Bundle, Jun 2004

swlist -l fileset|grep -i OnlineJFS gives me
# OnlineJFS B.11.11 Online features of the VxFS File System
OnlineJFS.VXFS-ADV-RUN B.11.11 VXFS-ADV-RUN


swlist -l fileset|grep -i jfs gives me

# JFS B.11.11 The Base VxFS File System
JFS.JFS-ENG-A-MAN B.11.11 JFS-ENG-A-MAN
JFS.JFS-JPN-E-MAN B.11.11 JFS-JPN-E-MAN
JFS.JFS-JPN-S-MAN B.11.11 JFS-JPN-S-MAN
JFS.VXFS-BASE-KRN B.11.11 The Base VxFS File System Kernel files
JFS.VXFS-BASE-RUN B.11.11 VXFS-BASE-RUN
JFS.VXFS-PRG B.11.11 Subproduct contains the necessary header files for prog env
# OnlineJFS B.11.11 Online features of the VxFS File System
OnlineJFS.VXFS-ADV-RUN B.11.11 VXFS-ADV-RUN
PHCO_26701.VXFS-BASE-RUN 1.0 JFS.VXFS-BASE-RUN
PHCO_29310.VXFS-BASE-RUN 1.0 JFS.VXFS-BASE-RUN
PHCO_29926.JFS-ENG-A-MAN 1.0 JFS.JFS-ENG-A-MAN
PHCO_29926.VXFS-BASE-RUN 1.0 JFS.VXFS-BASE-RUN
# PHKL_24026 1.0 JFS Filesystem swap corruption
PHKL_24026.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
PHKL_26104.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
PHKL_27734.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
PHKL_28185.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
# PHKL_28512 1.0 Fix for POSIX_AIO in JFS3.3
PHKL_29045.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
# PHKL_29115 1.0 JFS Direct I/O cumulative patch
PHKL_29115.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
PHKL_29335.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
# PHKL_30366 1.0 JFS3.3;ACL patch
PHKL_30366.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
PHKL_30582.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
PHKL_31212.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN
PHKL_32669.VXFS-BASE-KRN 1.0 JFS.VXFS-BASE-KRN

So I am not sure whether I do or do not have JFS. Looks like I do ?

Thanks,

[NMory]

Yes, you do have it....
So you will be able to extend the logical volume...but I recommend you to use the command line instead of SAM...well..that's me!!!

LN

[James R. Ferguson]

Hi Mike:

Yes, you do have ONLNIEJFS based on:

# swlist -l fileset|grep -i OnlineJFS

Also, when you create a volume group with 'vgcreate' the maximum number of PV (physical volumes) is fixed. By default the value is 16 as controlled by the 'max_pv' argument to 'vgcreate'.

When you increase the size of a *logical volume* you are not changing the number of PVs in the *volume group*. You are merely using space already available. You can add additional physical volumes to a volume group up to the 'max_pv' with 'vgextend'.

The suggestion to take some fraction of the remaining space you have is sound. Why waste. Shrinking a logical volume to reclain space to enlarge another one is rather troublesome. Often you must backup, remove and restore your data to a smaller logical volume -- unless you have recent versions of OnlineJFS.

Have a look at the 'lvm(7)' manpages for a quick overview. Look too, at the 'Managing Systems and Workgroups' guide for more information;

http://docs.hp.com/en/B2355-90950/B2355-90950.pdf

Regards!

...JRF...

[NMory]

My guess is that our previous partner, recommended you not grab the whole free capacity on this lvol that you want to extend, in case you need extra space for other lvols.

The 9 will not turn into 10, because 9 are the total of Physical Volumes you have assigned to your volume group.

If you want to add more Physical volumes to your volume group yuu will have to do a vgextend....Obviously you will need free available disks to do this on your array.

LN

[Mike Tufariello]

Sorry to keep beating a dead horse. But one last question. My BDF shows total, used and available space per lvol, per vg. Is the available space shown in the bdf differnt than the avaialable space shown in the vgdisplay or the logocal volumes in SAM? Is the avaialbe space in the bdf already allocated, where as the avaialble space shown in the vgdisplay has not been allocated.

Thanks to all for your help and patience.

[James R. Ferguson]

Hi (again) Mike:

Your 'bdf' shows total, used and available space per filesystems that have been mounted. The filesystems occupy space *within* a *logical volume* container. A logical volume is carved from n-number of physical *extents* of a volume group.

If you look at your 'vgdisplay' can see the extent size (in MB) as 'PE Size'. Multiple this by the 'Free PE' value to obtain potentially usable space for another logical volume or for adding to an existing one.

A filesystem has some overhead and so you will never get 100% of a logical volume for a filesystem's data space. Some fraction is required for inodes ("metadata"). The "available" space in a 'bdf' of a filesystem represents usable space for new files and directories or for increasing the size of existing ones. If you want to think of that available space as "allocated" to the filesystem, well, yes it is in a sense.

Regards!

...JRF...

[Victor BERRIDGE]

Hi again Mike,
I will continue after James... and reply you other question you asked me.
Me beeing a bit paranoid - hate to be short on disk space becaus if something goes wrong, finally you (the sysadmin) are to blame for not being proactive. I always keep enough spare to be able on a box to recreate if needed - the greatest file system it has...So if in need I dont have to wait for the san people to allocate more disks (which takes between 1-5 days...)
Having said that I would in your situation react by allocating to your lvol say 15 GB and now I still have 10Gb for any urgent need for all the other lvol (11) within this VG, what about your lvol8? think if this lvol needs space with 10GB - its not even 10% of its capacity, but here I admit I dont know the usage of the lvol mounted...

About PVs: These are what your system sees as physical volume or "prepared disks for LVM".
your vgdisplay says this group can contain a maximum of 16 PV and you have already 9 leaving for the future the option to add another 7
Now the paranoid speaking: knowing that have just 10GB left (remember I would have given 15..) I would start my claim for more PVs or atleast one!
If like here everything grows to 2X within less than 2 years you will not be able to do so because you have needed 9 disks to add and you cant...
So from my point of vue there is no more new lvol to be created in this vg and if you cant create an lvol in another its again time to ask for more PVs (and again you can start with one)
My point here is when vgcreate was done it was left with default values but they can be changed...
In your case - could be more than 16 -
And max extend: Max PE per PV 12799
will not allow to add LUNs greater than the ones (about 50GB)you have, for instance you coulnt add 72GB LUN or disk in this vg.
Have seen the size of this lvol and lvol8 I would have put them in a vg that could support up to 90GB LUN and would have changed the PE size to 8MB...

I hope I answered your questions
(And maybe brought up new ones the group will gladly reply...)

All the best
Victor

[Mike Tufariello]

James and Victor,

Thanks for the follow up. You have confirmed what I thought and also opened up more questions. To give you a little more info, lvol8, the mount point in question, contains static archived data consisting of 7 databases and should never grow beyond adding an 8th database. In hind sight it might have made more sense to put this in it's own vg.

James I know you spoke of issues with vg00. And by chance I also need to expand my /tmp mount point on vg00 another 10GB. My vgdisplay shows I have 74GB free. I have 2 internal system drives of 74 GB each in a mirror setup holding vg00.

Can I expand /tmp on vg00 the same way you have described that I can expand lvol8 on vgprod1 ? I assume I need a quite system and that /tmp is not being updated. I can check this with fuser?

Thanks again

[Victor BERRIDGE]

Hi Mike,
Since you hve online-JFS go ahead with SAM...
But 74GB free must be divided by 2 since you said you are mirrored (the 74GB is total for both disks...)


All the best
Victor

[Mike Tufariello]

So I went ahead and looked at the man pages for lvextend and fsadm. And read the response from all of you. I assume that if I have online JFS the file system on the changing lvol will unmount and mount automatically as long as the file system is not in use ?

And can I assume that if I use SAM to extend the lvol, and I have online JFS, SAM will unmount the file system, extend the file system, and mount the file system all in one step ?

Thanks,

[James R. Ferguson]

Hi (again) Mike:

When you have OnlineJFS there is no need to unmount a filesystem in order to resize it. With OnlineJFS when you execute 'fsadm' to resize a filesystem ther is *no* unmount. If there were, then you could not have any processes using the filesystem and this wouldn't be an "online" operation! :-))

Ditto, for using SAM instead of the commands at commandline. Remember, SAM is only a friendly front-end that builds the commands to perform the operation you have selected.

If you are more comfortable with SAM, use it, *but* afterwards, look at SAM's logs with its "viewer". You will begin to see how you could have done the same thing at commandline. That is, read the manpages and match the various switches and arguments to what SAM composed.

Regards!

...JRF...

[Victor BERRIDGE]

I would follow James advice, when using sam, it is worth having a look at its log to see what/how things are done,especially in the case sam will not launch... or cannot be used...
e.g. you dont have onlineJFS and you need to extend /var
...

Now this is what you would do - command line
extend the logical volume:
lvextend -L XXXX /dev/vgYY/lvolZZ
Increase on the fly the file system (Because you have onlineJFS)
fsadm -b VVVV /


All the best
Victor

[Mike Tufariello]

Where is the SAM log for these kind of things and what is the log file name?

After reading the lvextend man pages I noticed the lvreduce command. Is this as simple to use as the lvextend. Or is there an issue trying to reduce an lvol with a mounted file system? Can the lvreduce be run in SAM in the change lvol size option ?

[James R. Ferguson]

Hi (again) Mike:

In SAM, toggle 'Options -> View SAM Log' to see the SAM logfile.

Regarding 'lvreduce': If you 'lvreduce' a logical volume that contains a filesystem you potentially destroy the filesystem.

If you want to shrink a logical volume, but preserve the filesystem within, you need to first shrink the filesystem using 'fsadm'. This only works for current JFS releases.

If you want to shrink a logical volume and what to preserve the filesystem within, a guaranteed method is to *backup* the filesystem; 'lvreduce' the logical volume; 'newfs' the filesystem therein; and reload your backup.

Remember, a filesystem sits inside a container called a logical volume in LVM's world.

Regards!

...JRF...

[Mridul Shrivastava]

lvreduce can't be executed with filesystem mounted and it may cause data loss.
If you want to lvreduce then take backup and then it can be executed but you can't be sure about the data..

Sam log can be found at /var/sam/log/samlog

[Mike Tufariello]

James,

When you say a file system can be reduced online with only current versions of JFS, how would I know if my version supports that?

It might seem safer to backup and restore the filesystems as you suggested.