You mention that all the NSDs are metadata and data but you do not say how many NSDs are defined or the type of storage used, that is are these on SAS or NL-SAS storage? I'm assuming they are not on SSDs/flash storage.
Have you considered moving the metadata to separate NSDs, preferably SSD/flash storage? This is likely to give you a significant performance boost. You state that using the inode scan API you reduced the time to 40 days. Did you analyze your backup application to determine where the time was being spent for the backup? If the inode scan is a small percentage of your backup time then optimizing it will not provide much benefit. Fred __________________________________________________ Fred Stock | IBM Pittsburgh Lab | 720-430-8821 sto...@us.ibm.com From: "tomasz.wol...@ts.fujitsu.com" <tomasz.wol...@ts.fujitsu.com> To: "email@example.com" <firstname.lastname@example.org> Date: 02/08/2018 05:50 AM Subject: [gpfsug-discuss] Inode scan optimization Sent by: gpfsug-discuss-boun...@spectrumscale.org Hello All, A full backup of an 2 billion inodes spectrum scale file system on V126.96.36.199 takes 60 days. We try to optimize and using inode scans seems to improve, even when we are using a directory scan and the inode scan just for having a better performance concerning stat (using gpfs_stat_inode_with_xattrs64). With 20 processes in parallel doing dir scans (+ inode scans for stat info) we have decreased the time to 40 days. All NSDs are dataAndMetadata type. I have the following questions: · Is there a way to increase the inode scan cache (we may use 32 GByte)? o Can we us the “hidden” config parameters § iscanPrefetchAggressiveness 2 § iscanPrefetchDepth 0 § iscanPrefetchThreadsPerNode 0 · Is there a documentation concerning cache behavior? o if no, is the inode scan cache process or node specific? o Is there a suggestion to optimize the termIno parameter in the gpfs_stat_inode_with_xattrs64() in such a use case? Thanks! Best regards, Tomasz Wolski_______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org https://urldefense.proofpoint.com/v2/url?u=http-3A__gpfsug.org_mailman_listinfo_gpfsug-2Ddiscuss&d=DwICAg&c=jf_iaSHvJObTbx-siA1ZOg&r=p_1XEUyoJ7-VJxF_w8h9gJh8_Wj0Pey73LCLLoxodpw&m=y2y22xZuqjpkKfO2WSdcJsBXMaM8hOedaB_AlgFlIb0&s=DL0ZnBuH9KpvKN6XQNvoYmvwfZDbbwMlM-4rCbsAgWo&e=
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