These 'dirty' sysctl settings are configureable. For large sequential I/O it's desirable 'dirty' ratio/bytes to be bigger, while for small files/random I/O it's better to be kept low.
Best Regards, Strahil Nikolov В вторник, 5 октомври 2021 г., 08:52:20 ч. Гринуич+3, Ulrich Windl <ulrich.wi...@rz.uni-regensburg.de> написа: >>> Gang He via Users <users@clusterlabs.org> schrieb am 30.09.2021 um 03:55 in Nachricht <afb3d125-3573-a12f-406f-96724eaf1...@suse.com>: > > On 2021/9/29 16:20, Lentes, Bernd wrote: >> >> >> ‑‑‑‑‑ On Sep 29, 2021, at 4:37 AM, Gang He g...@suse.com wrote: >> >>> Hi Lentes, >>> >>> Thank for your feedback. >>> I have some questions as below, >>> 1) how to clone these VM images from each ocfs2 nodes via reflink? >>> do you encounter any problems during this step? >>> I want to say, this is a shared file system, you do not clone all VM >>> images from each node, duplicated. >>> 2) after the cloned VM images are created, how do you copy these VM >>> images? copy to another backup file system, right? >>> The problem usually happened during this step? >>> >>> Thanks >>> Gang >> >> 1) No problems during this step, the procedure just needs a few seconds. >> reflink is a binary. See reflink ‑‑help >> Yes, it is a cluster filesystem. I do the procedure just on one node, >> so i don't have duplicates. >> >> 2) just with "cp source destination" to a NAS. >> Yes, the problems appear during this step. > Ok, when you cp the cloned file to the NAS directory, > the NAS directory should be another file system, right? > During the copying process, the original VM running will be affected, > right? One issue, especially with large RAM systems is this: If you copy from a fast to a slow device, the RAM wil fil with dirty buffers, probably causing a read starvation (no discardable buffer available). So this can affect any unlelated process. (Actually in the past it affected the IPaddr monitor for us) However I think recent kernels (maybe it's SUSE specific) prevent the whole free RAM to be filled with dirty buffers. Regards, Ulrich > > Thanks > Gang > >> >> Bernd >> > > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/ _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
