[LU-12372] Look at increasing OST_MAXREQSIZE

• Status: Resolved
• Project: Lustre
• Type: Bug
• Priority: Minor
• Reporter: Patrick Farrell (Inactive)
• Assignee: Patrick Farrell (Inactive)
• Resolution: Not a Bug
• Severity: 3

Description

Currently, OST_MAXREQSIZE is limited to 16 KiB.  This limits the upper size of short i/o (LU-1757) to this size.  This ticket is to examine the implications of growing this limit, to, for example, 64 KiB - The concern is if we end up allocating the larger buffer size all the time for certain operations.

Basically, we/I need to examine the code to see if this is the case, and if it's not, we should look at increasing the upper limit, at least to see if it has a positive impact.

Issue Links

• is related to: LU-12910 osc.*.short_io_bytes parameter cannot...

Comments

[Andreas Dilger]

Acutally, OST_MAXREQSIZE is only used for the non-IO requests. OST_IO_MAXREQSIZE is used for IO requests and calculating OST_SHORT_IO_SPACE. It looks like OST_IO_MAXREQSIZE is slightly over 64KiB so we should be able to send a full 64KiB short write to the OST. If not, we could adjust it slightly.