[lustre-discuss] OST still has inodes and size after deleting all files

[Pavlo Khmel]

Thank you. I checked all those files with "ll_decode_filter_fid" and "lfs fid2path":

On OSS servers:

# umount /lustre/ost01
# mount -t ldiskfs /dev/mapper/ost01 /mnt/
# find /mnt/O/0/d*/ -type f
/mnt/O/0/d11/450605003
/mnt/O/0/d12/450605484
. . .

# ll_decode_filter_fid /mnt/O/0/d11/450605003
/mnt/O/0/d11/450605003: parent=[0x200019425:0x733f:0x0] stripe=0 stripe_size=1048576 stripe_count=1 layout_version=0 range=0

# umount /mnt
# mount -t lustre /dev/mapper/ost01 /lustre/ost01

On client:

# lfs fid2path /cluster [0x200019425:0x733f:0x0]
lfs fid2path: cannot find /cluster [0x200019425:0x733f:0x0]: No such file or directory

I got a reply "No such file or directory" for all those unknown files.
So I can assume those are "stray objects from deleted files".

Best regards,
Pavlo Khmel

> On 20 Jan 2024, at 04:45, Andreas Dilger <adilger at whamcloud.com> wrote:
> 
> 
> 
>> On Jan 19, 2024, at 13:48, Pavlo Khmel via lustre-discuss <lustre-discuss at lists.lustre.org <mailto:lustre-discuss at lists.lustre.org>> wrote:
>> 
>> Hi,
>> 
>> I'm trying to remove 4 OSTs. 
>> 
>> # lfs osts
>> OBDS:
>> 0: cluster-OST0000_UUID ACTIVE
>> 1: cluster-OST0001_UUID ACTIVE
>> 2: cluster-OST0002_UUID ACTIVE
>> 3: cluster-OST0003_UUID ACTIVE
>> . . .
>> 
>> I moved all files to other OSTs. "lfs find" cannot find any files on these 4 OSTs.
>> 
>> # time lfs find --ost 0 --ost 1 --ost 2 --ost 3 /cluster
>> 
>> real 936m8.528s
>> user 13m48.298s
>> sys 210m1.245s
>> 
>> But still: 2624 inods are in use and 14.5G total size.
>> 
>> # lfs df -i | grep -e OST0000 -e OST0001 -e OST0002 -e OST0003
>> cluster-OST0000_UUID  4293438576         644  4293437932   1% /cluster[OST:0]
>> cluster-OST0001_UUID  4293438576         640  4293437936   1% /cluster[OST:1]
>> cluster-OST0002_UUID  4293438576         671  4293437905   1% /cluster[OST:2]
>> cluster-OST0003_UUID  4293438576         669  4293437907   1% /cluster[OST:3]
>> 
>> # lfs df -h | grep -e OST0000 -e OST0001 -e OST0002 -e OST0003
>> cluster-OST0000_UUID       29.2T        3.8G       27.6T   1% /cluster[OST:0]
>> cluster-OST0001_UUID       29.2T        3.7G       27.6T   1% /cluster[OST:1]
>> cluster-OST0002_UUID       29.2T        3.3G       27.6T   1% /cluster[OST:2]
>> cluster-OST0003_UUID       29.2T        3.7G       27.6T   1% /cluster[OST:3]
>> 
>> I tried to check the file-system for errors:
>> 
>> # umount /lustre/ost01
>> # e2fsck -fy /dev/mapper/ost01
>> 
>> and
>> 
>> # lctl lfsck_start --device cluster-OST0001
>> # lctl get_param -n osd-ldiskfs.cluster-OST0001.oi_scrub
>> . . .
>> status: completed
>> 
>> I tried to mount OST as ldiskfs and there are several files in /O/0/d*/
>> 
>> # umount /lustre/ost01
>> # mount -t ldiskfs /dev/mapper/ost01 /mnt/
>> # ls -Rhl /mnt/O/0/d*/
>> . . .
>> /mnt/O/0/d11/:
>> -rw-rw-rw- 1 user1 group1 603K Nov  8 21:37 450605003
>> /mnt/O/0/d12/:
>> -rw-rw-rw- 1 user1 group1 110K Jun 16  2023 450322028
>> -rw-rw-rw- 1 user1 group1  21M Nov  8 22:17 450605484
>> . . .
>> 
>> Is it expected behavior? Is it save to delere OST even with those files?
> 
> 
> You can run the debugfs "stat" command to print the "fid" xattr and it will print the MDT
> parent FID for use with "lfs fid2path" on the client to see if there are any files related
> to these objects.  You could also run "ll_decode_filter_fid" to do the same thing on the
> mounted ldiskfs filesystem.
> 
> It is likely that there are a few stray objects from deleted files, but hard to say for sure.
> 
> Cheers, Andreas
> --
> Andreas Dilger
> Lustre Principal Architect
> Whamcloud
> 
> 
> 
> 
> 
> 
> 

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