On 07/10/2017 02:17 AM, NeilBrown wrote: > Another is to move the code around. In your case there are really just > 3 exports to each of 300+ clients (I assume "client.cs.uchicago.edu" in > the combined exports file is really different in different files). > So any one client only needs to consider 3 exports, not 300. This assumption is correct. We have ~300 clients and growing (slowly). > Could you test with this patch applied and see what > difference it makes? After being confused by conflicting test results and determining that the service nfs-server takes a bit longer to start than 'systemctl' will let you believe, I believe Niel's patch works. The new cache.c file I am using to test with: http://people.cs.uchicago.edu/~kauffman/nfs-kernel-server/test_with_patch/cache.c It also contains the official patch from this thread: http://marc.info/?l=linux-nfs&m=138900709311582&w=2 Building the new deb packages: http://people.cs.uchicago.edu/~kauffman/nfs-kernel-server/test_with_patch/build_deb.txt Install nfs-kernel-server and nfs-common debs on server and nfs-common on client. I reboot everything: client and server Run ssh for loop (no stracing) with the result that every user was able to ssh in under a second (I consider this to be a success). http://people.cs.uchicago.edu/~kauffman/nfs-kernel-server/test_with_patch/ssh_result_no-strace.txt I then used a larger sample size of users (~/f) and got a similar result. Now lets strace rpc.mountd while sshing with one user: $ time ssh -o BatchMode=yes $CLIENTHOSTNAME -l user_not_in_list_f Permission denied (publickey,password). real 0m0.352s user 0m0.020s sys 0m0.012s The resulting strace seems entirely reasonable: http://people.cs.uchicago.edu/~kauffman/nfs-kernel-server/test_with_patch/ssh_one_user_strace.txt $ for user in $(cat ~/users | grep -E "^g*"); do time ssh -o BatchMode=yes $CLIENTHOSTNAME -l $user; done The first few dozen users whos usernames happen to start with 'g': http://people.cs.uchicago.edu/~kauffman/nfs-kernel-server/test_with_patch/ssh_multiple_user_strace.txt -- Phil Kauffman Systems Admin Dept. of Computer Science University of Chicago kauffman@xxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
