Is there a way to mount a JFS with Direct I/O on system reboot?

oslevel -s
5300-06-04-0748


When using Enhanced JFS, is there a way to allow AIX to automatically
mount the file system with the Direct I/O option?

To do this now, I use the following command:

# mount -odio /samplefs

However, I would like to set up the file system so that it is
automatically mounted using that option. In the "smitty chjfs2"
screen, there is the following field:

Mount OPTIONS []

When I check the help for that field, it only mentions two options:

-------------------------------------------------------------------------------
The security-related mount options. You can specify the following
values:
- nosuid - Prevents execution of setuid and setgid programs from this
mount.
- nodev - Prevents open system calls of devices from this mount.
-------------------------------------------------------------------------------

Does anyone know if there is an entry I can add to the /etc/
filesystems or through smit that will auto-mount the file system with
the dio ?

I have not followed up with IBM AIX Support yet, just was wondering if
it was an undocumented but allowed option.

Thx,

Steve

steven_nospam at Yahoo! Canada <steven_nospam@yahoo.ca> wrote:[color=blue]
> oslevel -s
> 5300-06-04-0748[/color]

[color=blue]
> When using Enhanced JFS, is there a way to allow AIX to automatically
> mount the file system with the Direct I/O option?[/color]
[color=blue]
> To do this now, I use the following command:[/color]
[color=blue]
> # mount -odio /samplefs[/color]
[color=blue]
> However, I would like to set up the file system so that it is
> automatically mounted using that option. In the "smitty chjfs2"
> screen, there is the following field:[/color]
[color=blue]
> Mount OPTIONS [][/color]

You should be able to just type dio into that field and commit. Check
/etc/filesystems after you've done that and it ought to be listed on the
options line in the right fs stanza.

Regards,
Gregory Young

"Gregory Young" <usenet@outland.cc> wrote in message
news:g6dlhq$e30$1@skeeter.ucdavis.edu...[color=blue]
> steven_nospam at Yahoo! Canada <steven_nospam@yahoo.ca> wrote:[color=green]
>> oslevel -s
>> 5300-06-04-0748[/color]
>
>[color=green]
>> When using Enhanced JFS, is there a way to allow AIX to automatically
>> mount the file system with the Direct I/O option?[/color]
>[color=green]
>> To do this now, I use the following command:[/color]
>[color=green]
>> # mount -odio /samplefs[/color]
>[color=green]
>> However, I would like to set up the file system so that it is
>> automatically mounted using that option. In the "smitty chjfs2"
>> screen, there is the following field:[/color]
>[color=green]
>> Mount OPTIONS [][/color]
>
> You should be able to just type dio into that field and commit. Check
> /etc/filesystems after you've done that and it ought to be listed on the
> options line in the right fs stanza.
>
> Regards,
> Gregory Young
>[/color]

Easier way is to use the chfs command :

chfs -a options=dio <mountpoint>


Mark

Thanks Greg, Mark.

Yes, using smit (or chfs), I was able to add the option and it shows
in the /etc/filesystems as follows:

/tempfs:
dev = /dev/fslv00
vfs = jfs2
log = INLINE
mount = true
options = rw,dio
account = false

To test and see if ANY option value is accepted, I tried putting in an
invalid option to see what happens and got an error.

# umount /tempfs
# chfs -a options=rw,silly /tempfs
# mount /tempfs
mount: 0506-326 silly is not a valid flag.

That error did not appear on the "dio" setting I had added, so it is
probably an acceptable value for "options". I also see the value
listed with the lsfs command:

# lsfs /idsq01
Name Nodename Mount Pt VFS Size
Options Auto Accounting
/dev/idsq01lv -- /idsq01 jfs2 12845056
dio,rw yes no

Thx again.

Steve