WSUS on pool + Direct File I/O = Fail

SDWolf

I've been running WSUS (Windows Server Update Services) on my WHS for some time without issue, with the cache stored on a non-pooled drive.

Yesterday, I moved the WSUS cache to the pool by first creating the folder in DrivePool, then using wsusutil to move the cache to C:\ServerPool\ServerFolders\WSUS Data.  (WSUS's SQL database is still stored on a non-pooled drive.)

At first, all seemed well, until I set WSUS to download the "express installation files" (basically, the big offline installers, as opposed to the little webdownloaders).  This started WSUS downloading large amounts of data (expected), but shortly after, DrivePool appeared to hang.

After much trial and error (rebooting, setting WSUS to delayed start, etc), I traced the problem to Direct File I/O, both with and without Fast Directory Listing or Read Striping.  Disabling Direct File I/O has resolved the issue for now.

Logs are forthcoming.

WSUS 3.0SP2 (3.2.7600.226)

DrivePool build 4133

Paaland

I can see similar problems when downloading multiple large files from the internet. Say you for some reason want to allocate and start downloading 10 x 2 GB files. That usually does not go very well with DrivePool. Total hang and often a crash or timeout for the calling application. Works a treat for non-pooled shares.