Creating HFS on 200GB lvol.

[sandeep kumar_1]

Hi,

This involves performance concerns when a large HFS reaches 80% capacity. What are some of the things, I need to be concerned about. Can some of these issues be taken care of by using certain options while creating the FS.

I saw a reply from Trevor saying:
"For some more specifics I have seen previous posts by Bill Hassel on managing very large files and file systems. You may wish to do a forum search on his name."

But I cannot find the above post he was referring to.

So, Bill, if you are reading this, can you send me a pointer to it.

Thanks,
Sandeep

[Sandip Ghosh]

You can't create more than 128GB in HFS.

http://us-support.external.hp.com/cki/bin/doc.pl/sid=038873db107107ea7c/screen=ckiDisplayDocument?docId=200000058668755

Sandip

[Michael Tully]

Hi,

Have a look at this document also:

http://docs.hp.com/hpux/onlinedocs/5971-2383/5971-2383.html

[Michael Lampi]

If you take a look at the documents mentioned above they say that while you *CAN* make HFS file systems larger than 128GB, HP does not want to support them.

The main reason to not make them larger than 128GB is the amount of time it takes to perform an fsck if the system shuts down in an uncontrolled manner.

In addition, to answer the original question, the default settings of 10% free space can be cut down dramatically in large file systems. Minfree settings of 1% to 3% should be more than adequate to obtain decent throughput.

[Frank Slootweg]

For HFS, the primary concerns are file creation/deletion activity and growing/shrinking files.

If files are created one after the other and are not growing once created, i.e. everything is nicely contiguous on disk, then the filesystem can be filled to 100% (minfree 0%) without adverse (performance) consequences.

On the other hand, if the file system is very active (create/delete or/and grow/shrink) then the golden rule is to have a minfree of 10%.

[sandeep kumar_1]

It is intended to be a "daily build server" with lots of addition, deletion of large and small files, kind of FS torture test.

[Michael Lampi]

My answer still stands. The old 10% figure was for back in the days of 20MB - 500MB hard drives when it was easy to create files that filled the filesystem.

Leaving a 2 or 3% cushion on a 250GB file system gives you 5 to 7.5GB (!!) of free space to work with once the file system reports that it is full. This is plenty of free space to work with if your system ever fills up!