dd command question

[Galen Benson]

Good Day Everyone,

I'm trying to copy large files (over 2gb) from an mount point on my VA7100 to our SAN and when using the dd command, I simply get a message saying I/O Error.

We're running HPUX 11.0 & the command I'm using is dd if=/d05/exports/wdsa/060829.dmp.Z of=/newd05/exports/wdsa/060829.dmp.Z bs=1024

Our SAN vendor suggested that it may be the version of dd installed that is causing the problem, but I don't know how to find out
1. What version of dd we're running?
2. If necessary, how to upgrade this version to a version that will support files larger then 2gb.

Any help would be appreciated & as I'm leaving for the day, I can't check responses till tomorrow.

Thanks in advance,
Galen

[James R. Ferguson]

Hi Galen:

The first thing to verify is do you have 'largefiles' enabled on the destination filesystem. Do:

# mkfs -F vxfs -m /dev/dsk/cXtYdZ

...this output will show 'largefiles' or 'nolargeilfes' along with other attributes of the filesystem mounted on the device.

Regards!

...JRF...

[A. Clay Stephenson]

It's more likely that the filesystem does does support largefiles. You may need to run fsadm to enable largefiles (ie those larger than 2GiB). Although I don't think it will be necessary you can modify your dd to output to stdout and "outbushwhack" the 2GiB application limit (if it exists -- which I doubt). I'll all but sure it's the filesystem (although don't overlook ulimit and/or quotas).

if=/d05/exports/wdsa/060829.dmp.Z bs=256k > /newd05/exports/wdsa/060829.dmp.Z

Note that I changed your 1024 (bytes) to 256KiB -- that will make a huge performance difference.

[Adisuria Wangsadinata_1]

Hi Galen,

You need to check it first on the mount point on the SAN whether the file system can accept the large files :

To check if large files have been activated, please enter the following command:

# fstyp -v /dev/vgxx/lvolyy|grep f_flag

If the output shows:
f_flag: 16 = largefiles
large files are activated.

If the output shows:
f_flag: 0 = no largefiles
large files are inactive.

To activate the large files, use 'fsadm' as per ACS's info. Below is the format :

# usr/sbin/fsadm -F FSType -o largefiles /dev/vgxx/lvolyy

Hope this information can help.

Cheers,
AW

[Galen Benson]

Thanks all,

I thought the largefiles might be the problem too but in the /etc/fstab, the entry reads as follows:

/dev/svm/dsk/Amsys3_d05 /newd05 vxfs rw,suid,largefiles,delaylog,datainlog 0 2

Shouldn't this have setup the largefiles option?

The output I get when using James' suggestion is:

mkfs -F vxfs -o iinode=unlimited,bsize=2048,version=3,inosize=256,logsize=1024,nolargefiles /dev/svm/dsk/Amsys3_d05 10485760

and when checking with the fstyp command, it shows: f_flag: 16

So it does appear to be a filesystem problem, but here's what happens when using the following command to set large files:

fsadm -F vxfs -o largefiles /dev/svm/dsk/Amsys3_d05

vxfs fsadm: /dev/svm/dsk/Amsys3_d05 is not the root inode of a vxfs file sytem

Is there something I'm doing wrong here?
Thanks again,
Galen

[IT_2007]

Is it already mounted. what bdf output shows for this filesystem. don't rely on /etc/fstab and there might be typo's also.

I don't think "dsk" should exist on /dev/svm volume group. just check it out.

Once you confirm actual logical volume name and it's volume group then run fsadm command to enable largefiles option.

[Fabian Briseño]

Hello galen.

I dont know if this is related but I once had similar problem.

There was a file in .tar format that was being generated and every time this file was bigger than 2 GB it would fail.

The thing is, this problem was patch related, I installed a patch and my problem was solved

[A. Clay Stephenson · Accepted solution]

Use the mountpoint:

Rather than:
fsadm -F vxfs -o largefiles /dev/svm/dsk/Amsys3_d05
Use:
fsadm -F vxfs -o largefiles /newd05

By the way, the largefiles/nolargefile vxfs mount options tell you absolutely nothing about the filesystem's largefile capability.

[Galen Benson]

Thanks ACS, that fixed it. Thanks all for your quick responses!

[Galen Benson]

Thanks all