Re: IO transfer limits

Increasing SCSI_MAX_PHYS_SEGMENTS to 256 has doubled the IO size to 1MB. Thanks to all! cheers - jc Mike Christie wrote: > > john clyne wrote: >> Can anyone give me some guidance on where in the IO stack I might be >> running >> into a 512KB limit on IO transfer sizes

Re: IO transfer limits

ed, 2007-01-10 at 15:07 -0800, john clyne wrote: >> So given that the HBA max_sectors_kb looks sufficiently large, my >> interpretation of your article is the next place I need to look is at >> ajusting SCSI_MAX_PHYS_SEGMENTS. Sounds like i can only increase this to >> 256. Do

Re: IO transfer limits

What do the different hostX in /sys/class/scsi_host corespond to? There are seven hostX directories, 5 with sg_tablesize set to 128 and two set to 255. Is the implication that the hard limit is 255 * page_size, or is page_size simply the default? Mike Christie wrote: > > john clyne

Re: IO transfer limits

the limit or am I missing something? thanks - jc Douglas Gilbert wrote: > > john clyne wrote: >> Can anyone give me some guidance on where in the IO stack I might be >> running >> into a 512KB limit on IO transfer sizes to an external FC device? I've >> chec

IO transfer limits

Can anyone give me some guidance on where in the IO stack I might be running into a 512KB limit on IO transfer sizes to an external FC device? I've checked IO scheduler parameter (/sys/block//queue/{max_sectors_kb,max_hw_sectors_kb}. Both are set to 32767. I'm using Qlogic HBAs (qla2312), but I do