Increasing the DB Volume Size

illllm

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Hi All,

I need to increase the DB volume size..

From what I understand this is the process: assuming the server has
/tsminst1/dbvol1
/tsminst1/dbvol2
/tsminst1/dbvol3

1. add 512 GB lun to the server
2. mount the lun as /tsminst1/dbvol4
3. run command EXTEND DBSPACE /tsminst1/dbvol4

Restart the TSM Server.

Am I missing anthing?

Sorry about short impolite messages....in a critical situation now....Thank you so much !!
 
Just make sure the permissions (owner, group) are set on your newly created filesystem.
DB2/TSM will automatically redistribute to the new filesystems.
Not sure what other think, but I would wait until it has finished its redistribution before bouncing tsm.

Oh, take a full database backup before you do any work. :)

And yes....That simple :)
 
I start of with 8 luns, and extend them as needed. Less impact on db2. My choice, in this case would be to backup db and restore it on the new volumes. But, that is only if you got the possibility to take all down for a few hours.

-= Trident =-
 
will running backups at the same time have an impact on the DB or the leveling process? Is it okay to run backups at the cost of some performance impact ? Our DB is 7 TB in size. Yes :) i know its more than recommended and we will be moving some stuff off to another server...but we allowed it to grow after discussing with IBM
 
I start of with 8 luns, and extend them as needed. Less impact on db2. My choice, in this case would be to backup db and restore it on the new volumes. But, that is only if you got the possibility to take all down for a few hours.

-= Trident =-
Trident,
Few questions if you don't mind. When you say start off with 8 luns and extend are you saying extend the filesystem (AIX chfs command) or what exactly?
Why do a full restore to the volumes?
 
will running backups at the same time have an impact on the DB or the leveling process? Is it okay to run backups at the cost of some performance impact ?

With a 7TB database, I think your biggest issue will be actlog and arclog filling up. During the extend db, you cannot run database backups. So, if act and arc fill up, your system will go down. In this situation, I'd honestly look at what Trident is saying and do a full restore. Less chance of failure. Sorry, didn't recall your DB is that large.

Story time:
When I ran the extend db command I still had client backups coming in. I did start it during the slowest part of my day. It took about 12 hours if I recall correctly. My DB is sitting around 2.1TB now, and I think it was 1.8TB when I ran the extend db. DB is also sitting on a IBM V5K SSD shelf and running on a 16c Power8 box. In the last two hours of it leveling it was squeaky bum time, and I had to disabled ALL client sessions as well. Originally I was told I couldn't have downtime and clients must backup. I made a call near the end to disable session as arclog was at 97% full and actlog was approaching 80%. I don't recall where things stood at the end of the extend process but I kept sessions disabled and immediately ran a full dbbackup and only after things were cleared did I re-enable sessions. In short, my DB was 1.8TB, arclog was 768GB, actlog 256GB in size, and I was on the edge of a crash due to log space filling up.

Learn from my near failure, and play it safe!
 
Trident,
Few questions if you don't mind. When you say start off with 8 luns and extend are you saying extend the filesystem (AIX chfs command) or what exactly?
Why do a full restore to the volumes?
I fail, can't write this up on my phone / read illllm post about his 7tb db...

I was just thinking smaller DB's a full restore wouldn't be needed.
 
Trident,
Few questions if you don't mind. When you say start off with 8 luns and extend are you saying extend the filesystem (AIX chfs command) or what exactly?
Why do a full restore to the volumes?

Hi,
For AIX
cfgmgr (detect new lun zize)
chvg -g VG (extend VG)
chfs -a size=+64G /path (add diskspace)

Initially, my DB volumes are like 32Gb in size. Then they grow online in small steps (16 Gb each step)

-= Trident =-
 
I've always just given it 8 luns of max size that I can allocate. So,if I had 8, 256GB luns carved, db2 could use the entire space from all 8 at the get go if it wanted to.
DB2 automatically sees the new space with out issue (thats the part I'm confused about)?
Other than the old school unix philosophy of just giving it enough of what it needs, might I ask your reasoning? To me, just seems like a great way to get paged on the weekend by Nagios or something that watches filesystem space (and in my environment, then page the SAN team to work their voodoo on a weekend as well) :)
Flip side, for our non-AIX brethren expanding a filesystem on the fly can be tricky. Windows has gotten better at it, and linux is hit or miss depending if its in a lvm or not.

Apologies for the triple post earlier. My phone was being weird.
 
Hi,
For AIX
cfgmgr (detect new lun zize)
chvg -g VG (extend VG)
chfs -a size=+64G /path (add diskspace)

Initially, my DB volumes are like 32Gb in size. Then they grow online in small steps (16 Gb each step)

-= Trident =-

Hi Trident ,

I know its been while since you mentioned about this post , and i have a situation similar to what you have explained.

Ques 1 - After you add space to existing filesystem from AIX end , does tsm dynamically sees the increase ? Did you have to restart your instance ? Any other changes needs to be done from tsm ? in this scenario i assume all your DB volumes comes from same VG ?

Ques 2 - Is it possible to increase the directory-container pools in the same way as well ? For example if i start with 12 Directory Containers each 10 TB if there is a requirement to add more can i just simply make them 15 TB each ?
 
Hi Trident ,

I know its been while since you mentioned about this post , and i have a situation similar to what you have explained.

Ques 1 - After you add space to existing filesystem from AIX end , does tsm dynamically sees the increase ? Did you have to restart your instance ? Any other changes needs to be done from tsm ? in this scenario i assume all your DB volumes comes from same VG ?

Ques 2 - Is it possible to increase the directory-container pools in the same way as well ? For example if i start with 12 Directory Containers each 10 TB if there is a requirement to add more can i just simply make them 15 TB each ?

Q1. The chfs command does all the magic for you.
Q2. Yes, the same applies.
 
Q1. The chfs command does all the magic for you.
Q2. Yes, the same applies.

hey , thanks for the update , so when you say chfs does all the magic i am assuming that this can be done online even when TSM is up and it will dynamically increase the db volumes. That is great.

I have a situation where my tsm instances have 30 + db volumes each 100 GB ( whoever implemented did lot of mistakes ) .

I am wondering how to fix this any suggestions ?

Option 1 - Take full backup , restore to few filesystems ? any other options do we have ?
 
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