How to create raw devices of 1GB each to host the Oracle redo log files.

[gab_in]

Hi,

We have a HP-UX Itanium system running 11.31 with Oracle 10.2.0.2. I have two queries

1: How can we create 3 raw devices of 1GB each to host the Oracle redo log files?

2: Where are all the raw devices created in HP-UX and please tell me is .dbf file is raw?

Thanks
HU

[Yogeeraj_1]

hi Hu,

>1: How can we create 3 raw devices of 1GB each to host the Oracle redo log files?
To be able to create raw device files, you will first need to create your volume groups (VG) which comprise of one or several disk devices visible to the operating system.

ioscan -FknC disk

The above command will list down all the disk devices visible on your system.


>2: Where are all the raw devices created in HP-UX and please tell me is .dbf file is raw?
A raw device file simply represents a logical volume of a predefined size and normally we do not associate it with any file system.

.dbf is not a raw device. It may be a datafile created on a specific file system (mounted on a specific mount point e.g. /u01).

see also:
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=181260

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1144814

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1138171


if you need any further assistance, please let us know

kind regards
yogeeraj

[gab_in]

Thanks for the responce. Please find the bdf and ioscan output for our system and let me know how can I create the raw devices of 1GB each to host the Oracle redo log files.

# ioscan -funC disk
Class I H/W Path Driver S/W State H/W Type Description
===============================================================================
disk 1 0/0/2/1.0.16 UsbScsiAdaptor CLAIMED DEVICE OO Device Driver
/dev/deviceFileSystem/Usb/MassStorage/dsk/disk@hp-1008+294=A60020000001 /dev/deviceFileSystem/Usb/MassStorage/rdsk/disk@hp-1008+294=A60020000001
disk 2 0/4/1/0.0.0.0.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t0d0 /dev/dsk/c0t0d0s2 /dev/rdsk/c0t0d0 /dev/rdsk/c0t0d0s2
/dev/dsk/c0t0d0s1 /dev/dsk/c0t0d0s3 /dev/rdsk/c0t0d0s1 /dev/rdsk/c0t0d0s3
disk 8 0/4/1/0.0.0.1.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t1d0 /dev/rdsk/c0t1d0
disk 4 0/4/1/0.0.0.2.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t2d0 /dev/rdsk/c0t2d0
disk 7 0/4/1/0.0.0.3.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t3d0 /dev/rdsk/c0t3d0
disk 6 0/4/1/0.0.0.4.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t4d0 /dev/rdsk/c0t4d0
disk 9 0/4/1/0.0.0.5.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t5d0 /dev/rdsk/c0t5d0
disk 3 0/4/1/0.0.0.6.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t6d0 /dev/rdsk/c0t6d0
disk 5 0/4/1/0.0.0.7.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t7d0 /dev/rdsk/c0t7d0
# bdf
Filesystem kbytes used avail %used Mounted on
/dev/vg00/lvol3 1048576 315224 727640 30% /
/dev/vg00/lvol1 1835008 149840 1672048 8% /stand
/dev/vg00/lvol8 34078720 452912 33363144 1% /var
/dev/vg00/lvol7 3964928 2953272 1003808 75% /usr
/dev/vg00/lvol4 524288 497296 26848 95% /tmp
/dev/vg00/lvol6 6094848 4334224 1747264 71% /opt
/dev/vg00/lvol5 143360000 115324272 27820552 81% /home
/dev/vg02/lvol1 143327232 45181860 92011330 33% /data2
/dev/vg01/lvol1 143327232 4450858 130196649 3% /data1
DevFS 9 9 0 100% /dev/deviceFileSystem
#

[gab_in]

Just to update you that, We have the following disk free in our system. Please tell me how to create 3 raw devices of 1GB each to host the Oracle redo log files on these free disks.


disk 6 0/4/1/0.0.0.4.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t4d0 /dev/rdsk/c0t4d0
disk 9 0/4/1/0.0.0.5.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t5d0 /dev/rdsk/c0t5d0
disk 3 0/4/1/0.0.0.6.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t6d0 /dev/rdsk/c0t6d0
disk 5 0/4/1/0.0.0.7.0 sdisk CLAIMED DEVICE HP DG146A4960
/dev/dsk/c0t7d0 /dev/rdsk/c0t7d0

[Yogeeraj_1]

hi again,

It is recommended to create a log group with more than one member. Online redo log requires direct writes, point of serialization and speed.
If your application is log intensive that you would also wish to mirror the underlying disks.

So think well, what you really need, i would recommend you to have:
redo log groups 1, 3 .... on disks 1 and 3
redo log groups 2, 4 .... on disks 2 and 4

Coming to creation of Raw Devices, please follow steps as mentioned by SEP in the URL below:
http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1207916287836+28353475&threadId=510049


kind regards
yogeeraj