[Need Help]isboot (iSCSI boot driver) version 0.2.1

Alexander Motin mav at FreeBSD.org
Sat Jul 3 14:39:31 UTC 2010


Daisuke Aoyama wrote:
> I uploaded isboot 0.2.1.
> Now isboot supports R2T command and non-immediate mode.
> I believe that the compatibility of iSCSI target is improved.
> Please check it with your iSCSI target and NIC.
> Also this version supports task queue, which improves performance.
> My test machine got read 74MB/s, write 60MB/s (at bs=1m).
> Notes/Known Issues/Limitations:
> FreeBSD can't use transfer length > 64KB.

Since 8.0 FreeBSD can use any transfer lengths. 64K is a safety limit
for CAM SIMs that do not report maximum transfer size. If your driver
supports bigger transactions (and even if not), you should fill maxio
field in XPT_PATH_INQ response.

> It seems CAM tag is used only 2 of 64 tags.
> I don't know a reason, but MAXPHYS limit?

How many concurrent requests you are submitting? If you are testing it
with sequential read from file system - make sure you have sysctl
vfs.read_max set high enough. MAXPHYS does not affects number of
concurrent requests, only size of each one.

Alexander Motin

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