affinity breaks when trying to have more than 27 shares in the same group

[Maurice Escher]

Hi,

a customer of mine wanted to place a 28th share next to 27 others on the same back end using same host affinity scheduler hints.

But the share create request broke with an internal server error like
https://paste.opendev.org/show/btGOZSWsdSxplNOMQYif/

save_scheduler_hints() appends the IDs of each referenced share to the special internal metadata key https://opendev.org/openstack/manila/src/commit/0b99fdaa9a6ee33244e4560ddf2cc767afb5bf80/manila/share/api.py#L2367-L2385, but since the value column of share_metadata can only hold 1023 characters (see https://opendev.org/openstack/manila/src/commit/0b99fdaa9a6ee33244e4560ddf2cc767afb5bf80/manila/db/sqlalchemy/models.py#L538), it breaks when trying to add number 28 (it needs 36 characters per share uuid plus 1 char for the separator ',' and math.floor(1023/37)=27)

At least this needs some validation.

Better would be, if the list can get longer, e.g. by using additional metadata keys for storing that information or by an even bigger redesign..
Wdyt?

Best,
Maurice

[Vida Haririan (vhariria)]

See additional related discussions at https://meetings.opendev.org/meetings/manila/2023/manila.2023-08-17-15.00.log.html