connecting disk externally

[sreeja1611]

Hi,
We have an IBM RS/6000, 7043P, OS: Aix 4.3. We have 9.1x2 Gb disks internally connected. one for root and other for data. Now we are facing space problem. To solve, we are planning to connect an 18Gb disk external and extend the logical volumes to new disk. my doubt is that wolud be there any drop in accessing speed.

(or)

If I Move all the data on the old disk to new disk(connected externally) and makes the old disk free. would be there any drop in accessing speed.

pl. clear me.

Thanks in advance
Ravikumar

 

[victorv]

Hi,

for a disk, to be internal or external does not change
performances. Probably the new disk may be faster than
old; in this case you can configure your system as:

1) hdisk0 rootvg
2) hdisk1 othrvg
3) hdisk2 datavg

Condiderations:

A) to migrate datavg from disk1 to disk2 use
exportvg ( smitty vg ); then importvg on disk2
( when you see Available and still free og vg )

B) you can use hdisk1 for :

- additional paging space ( same value of hd6 ) to
split paging I/O on two devices.

- Install application program (cad,db,other) so that
when a command is executed, all 3 disks shares jobs.

C) If you want improve performances, you can add a
scsi adapter at which you attach the external disk,
instead to chain it whith other 2 disks, cdrom, and tape.
(Furthermore the new disk may be a LVD and if you use
the standard planar SCSI this may not have this feature,
then it goes but no in LVD mode; whithout a dedicated
adapter, I have had problem to connect new external disk
with tape ) .


D) Another configuration may be to use the second disk
as backup of rootvg, using mirror or alternate_rootvg.


B y e .

 

[aixat]

Hello Ravi,
Look at the

http://www.ibm.com

then search on Sales manual page.
For 18 gig external drive get the right adapter that goes for your system.
non IBM drives do not work.

 

[williambishop]

YOu CAN use non-IBM drives on external storage for the RS/6000's. Other than that, the victor hit the nail on the head.