There are so many things to look at and many tools for doing so (iostat, htop, nsdperf, mmdiag, mmhealth, mmlsconfig, mmlsfs, etc). I would recommend a review of the presentation that Yuri gave at the most recent GPFS User Group: https://drive.google.com/drive/folders/0B124dhp9jJC-UjFlVjJTa2ZaVWs
Cheers, -Bryan -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Peter Childs Sent: Tuesday, April 11, 2017 3:58 AM To: gpfsug main discussion list <[email protected]> Subject: [gpfsug-discuss] Spectrum Scale Slow to create directories This is a curious issue which I'm trying to get to the bottom of. We currently have two Spectrum Scale file systems, both are running GPFS 4.2.1-1 some of the servers have been upgraded to 4.2.1-2. The older one which was upgraded from GPFS 3.5 works find create a directory is always fast and no issue. The new one, which has nice new SSD for metadata and hence should be faster. can take up to 30 seconds to create a directory but usually takes less than a second, The longer directory creates usually happen on busy nodes that have not used the new storage in a while. (Its new so we've not moved much of the data over yet) But it can also happen randomly anywhere, including from the NSD servers them selves. (times of 3-4 seconds from the NSD servers have been seen, on a single directory create) We've been pointed at the network and suggested we check all network settings, and its been suggested to build an admin network, but I'm not sure I entirely understand why and how this would help. Its a mixed 1G/10G network with the NSD servers connected at 40G with an MTU of 9000. However as I say, the older filesystem is fine, and it does not matter if the nodes are connected to the old GPFS cluster or the new one, (although the delay is worst on the old gpfs cluster), So I'm really playing spot the difference. and the network is not really an obvious difference. Its been suggested to look at a trace when it occurs but as its difficult to recreate collecting one is difficult. Any ideas would be most helpful. Thanks Peter Childs ITS Research Infrastructure Queen Mary, University of London _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss ________________________________ Note: This email is for the confidential use of the named addressee(s) only and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you are hereby notified that any review, dissemination or copying of this email is strictly prohibited, and to please notify the sender immediately and destroy this email and any attachments. Email transmission cannot be guaranteed to be secure or error-free. The Company, therefore, does not make any guarantees as to the completeness or accuracy of this email or any attachments. This email is for informational purposes only and does not constitute a recommendation, offer, request or solicitation of any kind to buy, sell, subscribe, redeem or perform any type of transaction of a financial product. _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
