As others have said, yes, you can issue them manually anytime. To turn
off caching in XSTORE you can also use 'SET MDCACHE XSTORE OFF'.
What I would like to add is that you should not blindly follow the
Cookbook. Take the time to understand how MDC works, how it interacts
with your Linux guests, and how it can dyamically adapt its size relative
to the paging rate on your system. See also the BIAS option.
You can also use SET MDACHE to turn MDCACHE usage on/off on a user-by-use
r
basis or for specific MDISKs and real devices. See also the MINIOPT
statement in the directory.
Use MDC performance data to adjust the values you set to maximize the
benfit your site can get from MDC.
At this site (6G central and 1.5G XSTORE), I have 'SET MDCACHE STORAGE 0M
1792M', 'SET MDCACHE STORAGE BIAS .30', and 'SET MDCACHE XSTORE OFF'.
MDCACHE has also been disabled for Linux MDISKs used for SWAP.
Brian
On Mon, 5 Nov 2007 07:57:53 -0500, Anne D. Crabtree
<[EMAIL PROTECTED]> wrote:
>We increased the amount of central storage and added expanded storage to
>our VM IFL yesterday.
>
>When I issue 'Q MDC' I get this:
>
>
>
>Minidisk cache ON for system
>
>Storage MDC min=0M max=6144M, usage=9%, bias=1.00
>
>Xstore MDC min=0M max=1536M, usage=0%, bias=1.00
>
>
>
>According to the Virtualization Cookbook for Linux, AUTOLOG1's PROFILE
>EXEC should have:
>
>'cp set mdc stor 0m 128m' /* Limit minidisk cache in CSTOR */
>
>'cp set mdc xstore 0m 0m' /* Disable minidisk cache in XSTOR */
>
>
>
>I have added these statements to AUTOLOG1's PROFILE EXEC for next IPL.
>
>
>
>Can I safely issue these commands via MAINT now? Should I issue 'set
>mdc system off' first?
