sinhaparth5 opened a new pull request, #67536:
URL: https://github.com/apache/doris/pull/67536
### What problem does this PR solve?
Issue Number: close #62365
Problem Summary:
BE disk metrics come back empty when a data dir sits on an LVM
(device-mapper) volume.
`DiskInfo::get_disk_devices()` in `be/src/util/disk_info.cpp` looks up a
mount's device by comparing basenames: it takes the device column from
`/proc/mounts`, strips trailing digits (`sda2` -> `sda`), and checks that name
against the table `get_device_names()` built from `/proc/partitions`. For an
LVM mount, `/proc/mounts` shows `/dev/mapper/<vg-lv>`, which never matches the
`dm-N` name `/proc/partitions` uses, so the lookup always fails and no per-disk
metrics get installed for that mount.
`get_device_names()` already builds `_s_device_id_to_disk_id`, a table keyed
by the device's real `dev_t` (major:minor), for exactly this kind of lookup.
`get_disk_devices()` just wasn't using it. This PR resolves the mount's device
with `stat()` and matches on `st_rdev` against that table instead of comparing
names.
Also stopped trimming trailing digits off `dm-N` names in
`get_device_names()`. For a regular disk the digits mark a partition (`sda1`,
`sda2` are both `sda`), but for device-mapper the number identifies a distinct
logical volume, not a partition, so `dm-0` and `dm-1` were being collapsed into
one bogus `dm-` entry.
Added `be/test/util/disk_info_test.cpp` covering the extracted
`DiskInfo::strip_partition_suffix` helper.
### Release note
None
### Check List (For Author)
- Test
- [x] Unit Test
- [x] Manual test (add detailed scripts or steps below)
Manual test: hand-traced the `/proc/mounts` / `/proc/partitions` parsing
against a real LVM layout (`/dev/mapper/vg-lv0` mounted, backed by `dm-0`) to
confirm the new `stat()`-based match resolves correctly, plus the new unit test
for `strip_partition_suffix`. Also running the BE unit test build on a separate
box to confirm `DiskInfoTest.*` passes; will update this PR when that finishes.
- Behavior changed:
- [ ] No.
- [x] Yes. Disk metrics now populate for data dirs on LVM/device-mapper
mounts, which previously stayed empty.
- Does this need documentation?
- [x] No.
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