iSCSI in 7.0

Tom Samplonius tom at samplonius.org
Mon Nov 5 01:00:49 PST 2007


----- "James Mansion" <james at mansionfamily.plus.com> wrote:
> Have to say I was very pleasntly shocked to see iSCSI initiator
> support 
> in the 7.0 overview.
> 
> Is this the right place to ask about it?
> 
> Specifically, does FreeBSD ensure that socket buffers are allocated
> from 
> a set-aside pool
> for iSCSI data, so that iSCSI can be used for swap in a diskless 
> environment?  (Perhaps
> ideally it would be a mount-time option for this: its only really swap

  Well, since it is a kernel mode driver, it has to be use kernel memory.  There should be no issue with a swap deadlock, because the iSCSI client can't get more memory until some memory is swapped in.  But FreeBSD does not generally like running out kernel memory either.

> that needs it after all)
> 
> Linux fails to do this for iSCSI or AoE or nbd and prone (perhaps 
> theoretically prone,
> but its a worry) to deadlock when swapping over the network.

  I think Linux is using a kernel mode driver too.  Well, there were several iSCSI clients when I checked.  I'm not sure which you are looking at.

> Also, is the framework support such that it could be extended to
> support 
> coraid AoE or
> simple nbd like Linux, but without the limitation above?

  Well, FreeBSD has ggated for ndb like things.  It has been around for a while.

  AoE sounds completely retarded.  I hope it disappears before people think it is actually something serious.
> Thanks
> James


Tom


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