I follow that logic. Since you can't choose 9 (in the SLES10 drop
down), 5 works. Fewer than the "as many stripes as you have volumes"
recommendation...
But it still leaves my basic question -- how do you know or plan for
what the max size you can use is?
When we first set it up 45 mod 9s, 306GB, with 8 stripes we had to hunt
and peck all the way down to 275GB... So 31GB went into the stripes.
If I wanted a 300GB LVM, how do I know how much raw space I need?
Thanks,
Lee
Mark Perry wrote:
Lee Stewart wrote:
<SNIP>
For example, doing an LVM with 45 mod 9s. Round numbers math gives me
6.8GB/volume x 45 volumes = 306GB. That's close to what Max gives.
But what's the number with 8 stripes?
Hello Lee,
The idea is to put each of the specified stripes on a different DASD. I
have always used a number of stripes that was a factor of the number of
DASD in the VG.
So for your example of 45 DASD that would mean using a number of stripes
of either 9 or 5.
Also I have always added extra DASD to the VG pool in multiples of the
number of stripes, in the above example that would mean adding either 9
or 5 DASD at a time.
If you do not do as I suggest, then you can end up with more stripes on
one or more DASD than on others. This would defeat the purpose of using
stripes, which is to spread the I/O load "evenly" across multiple DASD.
If you want to use a number of stripes of 8, then either put 48 DASD in
your VG pool or reduce to 40. 48 has more factors, so with 48 DASD in
the VG you could choose a number of stripes from 2,3,4,6,8,12,16,24.
mark
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Lee Stewart, Senior SE
Sirius Computer Solutions
Phone: (303) 798-2954
Fax: (720) 228-2321
Email: [EMAIL PROTECTED]
Web: www.siriuscom.com
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