Vijay Adik vadik@us - IBM
Vijay Adik vadik@us - IBM
Vijay Adik vadik@us - IBM
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37<br />
<strong>IBM</strong> Advanced Technical Support - Americas<br />
The AIX IO stack<br />
Raw disks<br />
Raw LVs<br />
© 2009 <strong>IBM</strong> Corporation<br />
Application<br />
Logical file system<br />
JFS JFS2 NFS Other<br />
VMM<br />
LVM (LVM device drivers)<br />
Multi-path IO driver (optional)<br />
Disk Device Drivers<br />
Adapter Device Drivers<br />
Disk subsystem (optional)<br />
Disk<br />
Application memory area caches data to<br />
avoid IO<br />
NFS caches file attributes<br />
NFS has a cached filesystem for NFS clients<br />
JFS and JFS2 cache use extra system RAM<br />
JFS uses persistent pages for cache<br />
JFS2 uses client pages for cache<br />
Queues exist for both adapters and disks<br />
Adapter device drivers use DMA for IO<br />
Disk subsystems have read and write cache<br />
Disks have memory to store commands/data<br />
Write cache Read cache or memory area used for IO<br />
IOs can be coalesced (good) or split up (bad) as they go thru the IO stack<br />
April 17, 2009
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