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Ubuntu 16.10 forced me to migrate iSCSI targets to openscsi as previous package iscsitarget (also known as ietd - iSCSI Enterprise Target Daemon) was unsupported and removed.

Open-iscsi works, and the only thing I am missing is how to control target-side disk cache?

Previously I was setting IOMode=wb in ietd.conf. How can I achieve the same effect in open-iSCSI targets?

Target-side writeback cache is required to avoid extremely significant write speed degradation on RAID-6 arrays (500mb/sec -> 100mb/sec). If you commit every SCSI command to disk - you'll be updating parity all the time and your speed will be limited to 1 disk. Client-side write cache does not help with this problem.

BarsMonster
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1 Answers1

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I can't test on my laptop but,

NOTE: IOMode "wb" is ignored when employing blockio as it performs no caching.

WARNING: IOMode=wb could lead to serious data loss from an unexpected system failure (power loss, system crash). Use at your own risk!

If you are using blockio switch to fileio as this link documents:

WinEunuuchs2Unix
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