ceph squid - huge difference between capacity reported by "ceph -s" and "ceph df "
Hi, I just built a new CEPH squid cluster with 7 nodes Since this is brand new, there is no actuall data on it except few test files in the S3 data.bucket Why is "ceph -s" reporting 8 TB of used capacity ? Many thanks Steven [image: image.png]
Den sön 29 juni 2025 kl 17:22 skrev Steven Vacaroaia <stef97@gmail.com>:
Hi,
I just built a new CEPH squid cluster with 7 nodes Since this is brand new, there is no actuall data on it except few test files in the S3 data.bucket
Why is "ceph -s" reporting 8 TB of used capacity ?
Because each OSD will have GBs of preallocated data for the RocksDB, write-ahead-logs and other structures, and this counts against "raw available space", even if you don't have objects of this size put into the pools, the creation of the DBs and other things happened at osd creation, or when the first object was made, and are there even if you delete the object later. -- May the most significant bit of your life be positive.
Hi Janne Thanks That make sense since I have allocated 196GB for DB and 5 GB for WALL for all 42 spinning OSDs Again, thanks Steveb On Sun, 29 Jun 2025 at 12:02, Janne Johansson <icepic.dz@gmail.com> wrote:
Den sön 29 juni 2025 kl 17:22 skrev Steven Vacaroaia <stef97@gmail.com>:
Hi,
I just built a new CEPH squid cluster with 7 nodes Since this is brand new, there is no actuall data on it except few test files in the S3 data.bucket
Why is "ceph -s" reporting 8 TB of used capacity ?
Because each OSD will have GBs of preallocated data for the RocksDB, write-ahead-logs and other structures, and this counts against "raw available space", even if you don't have objects of this size put into the pools, the creation of the DBs and other things happened at osd creation, or when the first object was made, and are there even if you delete the object later.
-- May the most significant bit of your life be positive.
participants (2)
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Janne Johansson
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Steven Vacaroaia