raw files storage to storage

 
chunki
Occasional Contributor

raw files storage to storage

how can I do kind of copy (or make it available) raw devices from DS 2300 to eva 4400.
8 REPLIES 8
Patrick Wallek
Honored Contributor

Re: raw files storage to storage

With raw devices one of your only options will be 'dd'.

If this is a database, then there may be some database utilities you could use.

With so little information given about your environment it is hard to make any real recommendation.
Ganesan R
Honored Contributor

Re: raw files storage to storage

Hi Chunki,

If you want to move the entire data from one raw disk to another raw disk use dd with bigger block size.

Ex:

dd if=/dev/rdsk/c0t5d0 of=/dev/rdsk/c0t6d0 bs=1024k
Best wishes,

Ganesh.
chunki
Occasional Contributor

Re: raw files storage to storage


Thanks a lot Patrick & Ganeshan for your suggestions.

We're having oracle database files as raw devices, each database file has been configured as a logical volume.

Do I need to include the physical volumes or the logical volumes in the 'dd command'.





Thanks
john123
Trusted Contributor

Re: raw files storage to storage

U have to use raw logical volumes for dd,
Create the same logical sized logical volumes in the destination and use dd to copy
Provide the the dd'ed source to dest list to the DBA's they will be able to use this to make the new DB working.

Regards
John
chunki
Occasional Contributor

Re: raw files storage to storage

Thanks a lot guys

Gotta go ahead with it after a small presentation.








Thanks
chunki
Occasional Contributor

Re: raw files storage to storage

hi all

today i found that i'm able to use "mv" command on a D-Class server to move raw devices from one volume group to another.

Is it possible for me to do the same for migrating raw devices accross storage boxes (ds2300 & EVA4400) and if at all it is how reliable is it.


Regards
Chunki
Bill Hassell
Honored Contributor

Re: raw files storage to storage

> today i found that i'm able to use "mv" command on a D-Class server to move raw devices from one volume group to another.

Are you sure that you actually moved any data? mv is a renaming tool in the same filesystem. If you did soemthing like:

mv /dev/vg01/myraw /dev/vg02

then you did not move any data at all. Instead, you moved a device file to a different directory. Nothing changed. You can prove this by running a dd on that raw device -- you will see the same physical disks light up just as before because the device file refers to the hardware.

> Is it possible for me to do the same for migrating raw devices accross storage boxes (ds2300 & EVA4400) and if at all it is how reliable is it.

It will never work. The correct method is to use dd as mentioned before. The destination logical volumes must be the same size. You must use the bs option for any reasonable speed.

dd if=/dev/vg01/rmy_lvol of=/dev/vg02/rmy_lvol bs=512k

Without the bs= line, the transfer will ytake 20x-50x longer to complete.


Bill Hassell, sysadmin
chris huys_4
Honored Contributor

Re: raw files storage to storage

Hi Chunki,

How does the oracle dba, backup/restore, the raw oracle database files ?

I hope, if they are really raw oracle database files, via oracle utilities.

Let the oracle dba, use the same oracle utilities, to move them across different storage.

Best Regards,
Chris