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Feature #3673

closed

ceph-disk-prepare should provide an option for SSD alignment

Added by Faidon Liambotis over 11 years ago. Updated about 6 years ago.

Status:
Rejected
Priority:
Normal
Assignee:
-
Category:
-
Target version:
-
% Done:

0%

Source:
Community (user)
Tags:
Backport:
Reviewed:
Affected Versions:
Pull request ID:

Description

ceph-disk-prepare takes an option to use an external disk as a journal. It is commonly suggested that the journal is stored on an SSD and is also widely known that performance and resiliency characteristics of SSDs depends on alignment on the erase block. While sgdisk has a --set-alignment argument (defaults to 2048), there is no way to pass that via ceph-disk-prepare.

Note that because of #3255 (prepare triggers an activate), I couldn't even just create the symlink myself; I had to shutdown the OSD, --flush-journal just in case, change the symlink and --mkjournal again, for each OSD. That's hard and risky to automate using configuration management.

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