COMSTAR only supports 255 targets
255 targets ought to be enough for anybody, right? Well, perhaps not :-)
In cloud environments with a lot of guests where you're doing a 1:1 mapping between target and guest, you can quickly hit the 255 limit. We (EveryCity) just did. :-/
We knew this day would come but didn't think we'd hit it so soon, and now we have a SAN which has vastly more storage than we can utilise.
I'm not sure how difficult/easy this would be to up, but it might be useful for Nexenta who no doubt have customers who would like > 255 targets.
Updated by Alasdair Lumsden almost 12 years ago
Someone pointed out:
#define MAX_TARGETS 255 /* maximum targets that may be created */
I'm no kernel developer but it looks like the targets are stored in a linked list with a 32bit unsigned integer storing the count, so potentially the real maximum is 4bn?
crsd on IRC recompiled libiscsit.so.1 and tested creating more targets and nothing exploded immediately:
23:53 < crsd> AlasAway: http://pastebin.com/9ykAcD62 (not sure if it really works though :-)
Updated by George-Cristian Bîrzan over 9 years ago
I'd like to weigh in and say that we've been running several machines in production for months with as many as 500 targets, with no visible side effects.
Updated by Yuri Pankov over 7 years ago
Looking at the code, I don't see why we have that limit at all - may be we could just remove it instead of increasing?