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[Overview]
Our thanks to all who responed with a special thanks to the early responses
received from Paribas which got the ball rolling for us. Attached you will
find Ramesh Seshadri's write up on the steps we employed to install two
disks having one disk mirror the other. I am also including an example of
a general consensus type solution. Plus a few interesting point of
information we received along the way. And of course at the very bottom
you will find my original [Q] question.
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[Thank You]
I received responses from the following individuals.
Trevor_PARRY_at_paribas.com Trevor Parry
Lucien_HERCAUD_at_paribas.com Lucien HERCAUD
Russ_Fish_at_idx.com Russ Fish
digiunix_at_bellatlantic.net Larry Magnello
"GSNA99::LAURENTIUS_S"_at_gsnr01.denet.abb.de Steffi Laurentius
anthony.miller_at_vf.vodafone.co.uk Anthony Miller
GGuethlein_at_GiantofMaryland.com George Guethlein
Ramesh_Seshadri_at_dwd-is_at_ima.isd.state.in.us Ramesh Seshadri
David_Beltz_at_dwd-is_at_ima.isd.state.in.us David Beltz
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[Good will points of information]
"Normally you would mirror across 2 different SCSI busses otherwise
your performance may be reduced, and certainly you've lost the
resilience if the SCSI controller or power supply fail."
- Trevor Parry
"I will say that mirroring rz10 to rz11 is NOT an optimal scenario,
because both drives are on the same SCSI bus. If at all possible,
you should get the mirror drive on a different shelf."
- George Guethlein
"On Digital Unix, you do not mirror disks directly rather you mirror
the LSM volumes once they were created on the disks." LSM volumes
are virtual disks.
-Lucien HERCAUD
I forgot to include in my original [Q] query we use the advanced file
system. Eeeeek!
- Kevin Criss
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[SUMMARY] LSM, General advice solicited on mirroring disks
1. Create new disk labels for the two new disks using the following
commands.
disklabel -t advfs -rw rz10 /dev/rrz10c
By using rrz10c, we are indicating that the entire disk, which is
normally the 'c' partition, is to be configured as advfs.
disklabel -t advfs -rw rz11 /dev/rrz11c
2. Create new disk volume by adding the two new disks to a new volume
using the following command.
voldiskadm
Select the option 'Add or Initialize a Disk'. Enter the new disk
as rz10 [not rrz10c]
Enter the disk group as dwddg
[new group gets automatically created]
Execute the same steps for rz11 and enter the same group name, dwddg.
3. Check for the newly created volume using the following command.
volprint -ht A
4. Observe the free space available in the two disks attached to the
'dwddg' disk group by using the following command.
voldg -g dwddg free
Note down the least of the free space shown against the two disks.
In our case, the free size should be the same as both of the disks
are of identical sizes. (should be approx. 4 GB)
5. Create a new volume and a mirror copy of one of the disks on the
other using the following command.
volassist -g dwddg make dwddg_vol1 <size as noted in 4 above>
mirror=yes
A new volume dwddg_vol1 gets created. We need not mention the disk
names, rz10 and rz11 here as the volassist command automatically
checks for the disks and its free sizes in the disk group, dwddg,
and organizes the mirror. In our case, it is made easier as both the
disks are of identical configuration.
6. Create a file domain using the following command.
mkfdmn /dev/vol/dwddg/dwddg_vol1 dwd_domain
7. Create filesets and mount points for this domain. From this point,
we will be referring to the domain names and not the LSM volume
names.
8. Save the LSM volume configuration using the following command.
volsave
Thanks - Ramesh
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[General Consensus Solution] the George Guethlein variation
1) disklabel -z rz10; disklabel -rw rz10 rzxx
2) disklabel -z rz11; disklabel -rw rz11 rzxx
** 1 & 2 will zero out any label info on the drives and
relabel them with the default info from the physical drive.
3) voldisksetup -i rz10 privlen=1024 nconfig=2 nlogs=2
4) voldisksetup -i rz11 privlen=1024 nconfig=2 nlogs=2
** 3 & 4 will initialize the physical drives in the LSM
diskfarm, reserving 1024 blocks of 512 bytes for LSM configuration
info space, and each LSM device media
will contain 2 copies of the LSM configuration database and 2
copies of the LSM configuration logs.
5) voldg -g rootdg adddisk rz10=rz10
6) voldg -g rootdg adddisk rz11=rz11
** 5 & 6 will add the "new" LSM devices into the specified
LSM diskgroup ("rootdg" in my example).
7) volassist -g rootdg make New_Vol Vol_Size rz10
** ie. volassist -g rootdg make new_vol 4000m rz10
would make a 4GB LSM volume (new_vol) on rz10
8) volassist -g rootdg mirror New_Vol rz11
** ie. volassist -g rootdg mirror new_vol rz11
would create a amirror of new_vol on rz11
9) At this point you can create a UFS or AdvFS filesystem
on the LSM volume and mount it. I use AdvFS myself, as follows :
mkfdmn /dev/vol/rootdg/new_vol new_dmn mkfset new_dmn new_fs
mount -t advfs new_dmn#new_fs /tmp
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[Q] LSM: General advice solicited on mirroring disks
We are adding Two [2] RZ1CB-CA type disks that have 4.3 gigabytes of
storage capacity each. These are new disks which have never been used
and currently are not labeled.
rz10 at scsi1 target 2 lun 0 (LID=3) RZ1CB-CA rz11 at scsi1 target 3
lun 0 (LID=4) RZ1CB-CA
We would like to use LSM command line directives to configure rz11 as
a mirror of rz10.
Any information that can be provided regarding this procedure would be
appreciated.
Thanks - Kevin
Received on Wed Nov 11 1998 - 16:08:16 NZDT