Ashwani Raina has posted comments on this change. ( http://gerrit.cloudera.org:8080/20680 )
Change subject: KUDU-3523 Use f_bsize as Kudu block size instead of st_blksize ...................................................................... Patch Set 3: Generally, both st_blksize and f_bsize are same when we are working on a native filesystems on linux e.g. ext3/ext4. The use case that you have mentioned here seems to be unusual. I noticed the filesystem type that you are using is of type overlayfs which IIUC is a unionfs/layeredfs that probably had layers of different filesystem type. I can't say for sure, but there is a possibility that in layeredfs, the st_blksize may differ from the f_bsize depending on which filesystem driver is used for get that information. I am planning to test this out on local setup. Will try to share the details once I complete the test or you can update here if you are already aware of it. I am very much interested in knowing more about the setup you are using, what all actual filesystems are constituting this setup, purpose of having a overlayfs setup, directory structure used in overlayfs setup, etc. LBM needs hole punching support from underlying filesystem (ext4 does provide that currently). However, I am not quite clear on what it would mean if Kudu data is residing on overlayfs that has multiple different filesystems underneath it and there is one filesystem that doesn't support hole-punching. Maybe it would be worth an exercise to evaluate behaviour of POSIX APIs (used in Kudu) on overlayfs mount-point. IIUC, overlayfs is just an abstraction layer and all the requests go to targeted underlying file-system so it shouldn't matter much but it is worth a try though because what all underlying filesystems are supported for Kudu is something that is not clearly visible when it is an overlayfs setup. TL;DR: You could provide more information on the following points: 1. Provide some more information about the directory setup and how it uses overlayfs. 2. Check if all the underlying filesystems support hole punching (if Kudu is using LBM). 3. Purpose of using overlayfs. 4. Can you try reproduction with same steps on a regular underlying filesystem e.g. ext4 (just to rule out other possibilities)? -- To view, visit http://gerrit.cloudera.org:8080/20680 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I04343caf5fe377a4fa9b57e6e450307e6b995928 Gerrit-Change-Number: 20680 Gerrit-PatchSet: 3 Gerrit-Owner: Wang Xixu <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Ashwani Raina <[email protected]> Gerrit-Reviewer: Attila Bukor <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Reviewer: Wang Xixu <[email protected]> Gerrit-Reviewer: Yifan Zhang <[email protected]> Gerrit-Reviewer: Yingchun Lai <[email protected]> Gerrit-Comment-Date: Wed, 22 Nov 2023 14:15:42 +0000 Gerrit-HasComments: No
