I asked about this almost 2 years ago. I was thinking along the same line as yourself. I was told it wasn't available AND if it could be disabled, it may break a lot of code. Linux caching also includes write caching. So your writes don't immediately pass to CP (much less the I/O boundry) immediately.
Anyway, after playing with Linux for almost 2 years, I don't think disabling Linux caching would be a good idea, even if it was doable.
Big reason is caching has the least amount of overhead the closer you are to the application that is doing the I/O. So Linux caching doesn't envolve the overhead of going to CP to MDcache, much less going through the hardware boundary to controller cache (ok, so now a days it's most likely, controller cache, raid cache and drive cache...any others?)
So disabling Linux cache would only be good for mdcache, if multiple Linux machines where sharing the same physical cylinders. And sharing packs, which was discussed last week, doesn't seem to be too easy. Some low volume packs may be easy, but the root, usr and such are somewhat hard to do. (Now if you have the money for LinuxCare....)
I only have 17 images, each sufficiently unique enough to make sharing packs difficult, that I gave up on this idea. However, I do share a pack containing RPMs, and TAR files.
I went back to vdisk (or for low priority images, tdisk) swap space, with a second, lower priority allocation of some old Ramac drives.
Tom Duerbusch THD Consulting
-----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Dave Jones Sent: Tuesday, July 13, 2004 12:20 PM To: [EMAIL PROTECTED] Subject: Linux on zSeries and file caching...
Folks, does anyone know how to build a Linux 2.4.x kernel that has Linux file caching disabled? I want to disable Linux's file caching and let CP's minidisk caching functions do it instead, and to reduce the virtual storage requirements for the guest.
TIA.
-- Dave Jones Houston, TX
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