On 11/29/21 11:36 AM, dai.ngo@xxxxxxxxxx wrote:
On 11/29/21 11:03 AM, Chuck Lever III wrote:Hello Dai!On Nov 29, 2021, at 1:32 PM, Dai Ngo <dai.ngo@xxxxxxxxxx> wrote: On 11/29/21 9:30 AM, J. Bruce Fields wrote:On Mon, Nov 29, 2021 at 09:13:16AM -0800, dai.ngo@xxxxxxxxxx wrote:Hi Bruce, On 11/21/21 7:04 PM, dai.ngo@xxxxxxxxxx wrote:On 11/17/21 4:34 PM, J. Bruce Fields wrote:On Wed, Nov 17, 2021 at 01:46:02PM -0800, dai.ngo@xxxxxxxxxx wrote:On 11/17/21 9:59 AM, dai.ngo@xxxxxxxxxx wrote:I ran all tests in nfsv4.1 and nfsv4.0 with courteous and non-courteousOn 11/17/21 6:14 AM, J. Bruce Fields wrote:On Tue, Nov 16, 2021 at 03:06:32PM -0800, dai.ngo@xxxxxxxxxx wrote:Last time I ran 4.0 OPEN18 test by itself and it passed. I will run all OPEN tests together with 5.15-rc7 to see if the problem you'veJust a reminder that this patch is still waiting for your review.Yeah, I was procrastinating and hoping yo'ud figure out the pynfsfailure for me....seen still there.5.15-rc7 server. Nfs4.1 results are the same for both courteous and non-courteous server:Of those: 0 Skipped, 0 Failed, 0 Warned, 169 PassedResults of nfs4.0 with non-courteous server:Of those: 8 Skipped, 1 Failed, 0 Warned, 577 Passedtest failed: LOCK24 Results of nfs4.0 with courteous server:Of those: 8 Skipped, 3 Failed, 0 Warned, 575 Passedtests failed: LOCK24, OPEN18, OPEN30 OPEN18 and OPEN30 test pass if each is run by itself.Could well be a bug in the tests, I don't know.The reason OPEN18 failed was because the test timed out waiting for the reply of an OPEN call. The RPC connection used for the test was configured with 15 secs timeout. Note that OPEN18 only fails when the tests were run with 'all' option, this test passes if it's run by itself. With courteous server, by the time OPEN18 runs, there are about 1026courtesy 4.0 clients on the server and all of these clients have openedthe same file X with WRITE access. These clients were created by the previous tests. After each test completed, since 4.0 does not have session, the client states are not cleaned up immediately on the server and are allowed to become courtesy clients. When OPEN18 runs (about 20 minutes after the 1st test started), it sends OPEN of file X with OPEN4_SHARE_DENY_WRITE which causes the server to check for conflicts with courtesy clients. The loop that checks 1026 courtesy clients for share/access conflict took less than 1 sec. But it took about 55 secs, on my VM, for the server to expire all 1026 courtesy clients. I modified pynfs to configure the 4.0 RPC connection with 60 seconds timeout and OPEN18 now consistently passed. The 4.0 test results are now the same for courteous and non-courteous server: 8 Skipped, 1 Failed, 0 Warned, 577 Passed Note that 4.1 tests do not suffer this timeout problem because the 4.1 clients and sessions are destroyed after each test completes.Do you want me to send the patch to increase the timeout for pynfs? or is there any other things you think we should do?I don't know. 55 seconds to clean up 1026 clients is about 50ms per client, which is pretty slow. I wonder why. I guess it's probably updating the stable storage information. Is /var/lib/nfs/ on your server backed by a hard drive or an SSD or something else?My server is a virtualbox VM that has 1 CPU, 4GB RAM and 64GB of harddisk. I think a production system that supports this many clients shouldhave faster CPUs, faster storage.I wonder if that's an argument for limiting the number of courtesy clients.I think we might want to treat 4.0 clients a bit different from 4.1 clients. With 4.0, every client will become a courtesy client after the client is done with the export and unmounts it.It should be safe for a server to purge a client's lease immediately if there is no open or lock state associated with it.In this case, each client has opened files so there are open states associated with them.When an NFSv4.0 client unmounts, all files should be closed at that point,I'm not sure pynfs does proper clean up after each subtest, I will check. There must be state associated with the client in order for it to become courtesy client.
pynfs 4.0 test uses LOOKUP, OPEN with OPEN4_CREATE to create the test file and uses PUTFH and REMOVE to remove the test file when done. I don't see where the open state associated the removed file being freed by nfsd_remove. I guess for 4.0, the open state remains valid on the server until the client lease expires. I attached the pcap of OPEN18 test for reference. -Dai
so the server can wait for the lease to expire and purge it normally. Or am I missing something?When 4.0 client lease expires and there are still states associated with the client then the server allows this client to become courtesy client. -DaiSince there is no destroy session/client with 4.0, the courteous server allows the client to be around and becomes a courtesy client. So after awhile, even with normal usage, there will be lots 4.0 courtesy clients hanging around and these clients won't be destroyed until 24hrs later, or until they cause conflicts with other clients. We can reduce the courtesy_client_expiry time for 4.0 clients from 24hrs to 15/20 mins, enough for most network partition to heal?, or limit the number of 4.0 courtesy clients. Or don't support 4.0 clients at all which is my preference since I think in general users should skip 4.0 and use 4.1 instead. -Dai-- Chuck Lever
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