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Our applications write data to NAS that is mounted to multiple servers (running both redhat and suse). Generally this works fine, but several times a week the NAS seems to get out of sync. The file being written is often correct on one machine, but not the others. Scenario:

  1. Our application writes a file to the NAS from server-A
  2. If we login to server-A, and access the file that was just written to NAS, it is correct and complete
  3. If we login to server-B and access the exact same file from the exact same NAS mount, the file isn't complete
  4. If we login to server-C and access the exact same file from the exact same NAS, the file isn't complete, but matches what we saw on server-B

server A, B, and C /etc/fstab

eg-nasclnt-a02:/vol/ct_wlnvtest_nosnap/othertreatisewlnvtest /wlnv/analytical-cc/othertreatise nfs bg,hard,intr,tcp,nfsvers=3,rsize=32768,wsize=32768

server-A file check

[serverA] md5sum /wlnv/analytical-cc/othertreatise/data/WLAWDB.PROD\@A.WLNV.WFTTEXT.B1.35826/conversion/output/WLAWDB.PROD\@A.WLNV.WFTTEXT.B1.35826_w_3rd_wfttext.xml   
5e0116be3c26280a2cf8e6b83147a50c  /wlnv/analytical-cc/othertreatise/data/WLAWDB.PROD@A.WLNV.WFTTEXT.B1.35826/conversion/output/WLAWDB.PROD@A.WLNV.WFTTEXT.B1.35826_w_3rd_wfttext.xml

server-B file check

[serverB] md5sum /wlnv/analytical-cc/othertreatise/data/WLAWDB.PROD\@A.WLNV.WFTTEXT.B1.35826/conversion/output/WLAWDB.PROD\@A.WLNV.WFTTEXT.B1.35826_w_3rd_wfttext.xml
81dead688c6f5632d9b25f226b45e7f4  /wlnv/analytical-cc/othertreatise/data/WLAWDB.PROD@A.WLNV.WFTTEXT.B1.35826/conversion/output/WLAWDB.PROD@A.WLNV.WFTTEXT.B1.35826_w_3rd_wfttext.xml

server-C file check

[serverC] md5sum /wlnv/analytical-cc/othertreatise/data/WLAWDB.PROD\@A.WLNV.WFTTEXT.B1.35826/conversion/output/WLAWDB.PROD\@A.WLNV.WFTTEXT.B1.35826_w_3rd_wfttext.xml
81dead688c6f5632d9b25f226b45e7f4  /wlnv/analytical-cc/othertreatise/data/WLAWDB.PROD@A.WLNV.WFTTEXT.B1.35826/conversion/output/WLAWDB.PROD@A.WLNV.WFTTEXT.B1.35826_w_3rd_wfttext.xml

What controls the NAS mounts propogation delay or caching? What should I check to correct this?

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"NAS" doesn't tell us enough about what you're running, nor do we understand how you're syncing data -- just multiple mount points? What are your mount options -- guessing NFS here -- Sync/Async? Different options on the NAS boxes for those protocols? – Jon Lasser Feb 1 '10 at 21:58
up vote 0 down vote accepted

I don't know the root cause of the problem, but adding this mount option has fixed it: actimeo=1

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