1Tb filesystem

[bonsky]

question,

if i am to create a 1Tb filesystem which will be alotted to one of our application as database, eill i be having problems with it? Is there any special steps that i have to take in to consideration in creating this filesystem? Or i'll just make them as ordinary fileystem and just choose large file system in smitty instead?

thanks in advance.

 

[aixqueen]

My question is are you talking filesystem up to 1 Ter or a file itself?
The question is filesystem vs files.....Are the files going to be bigger than 2GB
Large File enabled is for Files bigger than 2 GB

Another question is, we are talking 5L not 4.3? If 5L and you want terabyte. for a file, ..I believe you are talking jfs2 (which you must select on install along with the 64 bit kernel) Just filesystem is another issue.

======================

AIX Version 4.3.3

Open files per process = 32,767
Threads per process = 32,767
Max size of shared or mapped files per memory segment = 2GB
Total open files per system = 1,000,000
Support for files up to 64 GB/Filesystems up to 128 GB (supported)
Maximum size for shared or mapped files 2GB
(but this does not mean that your application can handle or work with files larger
than 2 GB)


=====================

AIX 5L
JFS2 is a new file system type providing the capability to store 1 Terabyte files. It
is the default file system for the 64-bit kernel. Cachefs is enhanced to work under
the 64-bit kernel and will support large file systems. It will handle files larger than
2 GB, although the cache file does not have to be larger than 2 GB. As a result,
data can be accessed faster.

AIX 5.1 offers new flexibility for 32-bit "maxdata" programs by allowing the
segments of the data heap (up to 8 256 MB segments) to be created dynamically.

Functions JFS2 JFS
--------------------------- -------------------- --------------
Fragments/Block Size 512-4096 Block sizes 512-4096 Frags
Architectural Maximum 4 Petabytes 64 GBytes File Size
Maximum File Size Tested 1 Terabyte 64 GBytes
Architectural Maximum File 4 Petabytes 1 Terabyte System Size
Maximum File System Size 1 Terabyte 1 Terabyte
=====================

IF we are talking LARGE FILE ENABLED...some warning.
Some warnings for Large File Enabled........
Your application must be able to handle files bigger than 2GB. Many
cannot
Don't do large file enabled file systems if you aren't planning on having
files bigger than 2GB, because the overhead for inodes will be larger.
tar and cpio do not currently support files larger than 2GB. Only
backup/restore programs seem to at this point.
Large File System enabled is NOT compatible with AIX 3.2 systems.
Watch your ulimit. This is defined in /etc/security/limits. This will allow
users to create files above the set limit.
Applications must be recompiled using the "-D_LARGE_FILES flag
and must be compiled on a AIX 4.2.x or higher.
See Info-explorer under "large files" for more information.
Some users report that .....Write performance using Large-Files
enabled filesystems appear to be slower. than regular JFS
filesystems...Read performance was not usually affected.
There does not appear to be a way to change or modify existing File
systems to make them Large File System enabled. You must recreate
them with the -bf=true option or in smit.

How do you set up Large Filesystem Enabled filesystems?

1) Make sure you check your ulimit (in .profile or /etc/security/limits) and set
to unlimited -1

2) Create a new filesystem with Large File System Enabled....either from the
command line with the -a bf=true or through smit.. Smit, System Storage
Mgt, File Systems, Add/change/show/delete a File System, Journal File
System, Add a Journal File System, Add a large File enable Journal File
System.

3) Recompile any applications that can handle Large file with the
-D_LARGE_FILES flag in C or get the patches for your Database to handle
the option.....

Large File info:

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/aixbman/admnconc/lg_files_under.htm

Overview:

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/aixprggd/genprogc/lrg_prg_support.htm

commands not supported :

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/cmds/aixcmds6/AppendixA.htm

-------------------

Hope this helps you?

 

[bonsky]

thanks a llot for info.
i believe i will be needing a file system that can support up to 1Tb, for files.. i guess, a single file might be more than 2 Gb, for we are going to store mpegs, videos and others.
From your comment, Large file system will do.. but then do i need to edit the etc/ulimit once i chose enble large file systems in creating file systems? or is it automatically enabled to create a file greater than 2gb?
thanks in advance

 

[aixqueen]

You only need the large file enabled if you are doing files greater than 2 GB...
and yes, you manually have to change the /etc/security/limits file....
or ulimit params...or it doesn't allow you to do it.
And you have to select large file enabled when you create it.