MAX I/O SIZE IN HP-UX

[KAMARULZAMAN HJ ALI]

Dear All!

My machine is HP V2600 with HP-UX 11.00.
How to check max i/o size configured in HP UX. Is the max i/o size configurable (can be changed)

TQVM

[Stefan Farrelly]

I dont think you can change it, its specified in /usr/include/sys/streams.h

#define MAXIOCBLKSZ 8192

[Armin Feller]

I think the max i/o depends on your hardware and the traffic, e.g. how fast is the processor, the harddisks, the buses (scsi, fc, ...), ... and how much datas are currently on the way.

So what i/o you are thinking about? disk-, memory-, cpu-, ...-i/o

Regards ...
Armin

[Armin Feller]

Here a list of all documented I/O Kernel tunables:

?? Asynchronous I/O Subsystem
aio_listio_max
Max number of AIO operations that can be specified in a lio_list() call

aio_max_ops
Maximum number of AIO operations that can be queued at any time

aio_physmem_pct
Maximum number of AIO operations that can be specified in a lio_list() call

aio_prio_delta_max
Maximum slowdown factor; greatest priority reduction allowed in aiocb's aio_reqprio field


?? Character-Mode I/O Streams Parameters
NSTRBLKSCHED
Factory use only. Do not change value.

NSTREVENT
Maximum number of outstanding streams bufcalls that are allowed to exist at any given time on the system.

NSTRPUSH
Maximum number of streams modules that are allowed to exist in any single stream at any given time on the system.

NSTRSCHED
Maximum number of streams scheduler daemons that are allowed to run at any given time on the system.

STRCTLSZ
Maximum number of control bytes allowed in the control portion of any streams message on the system.

STRMSGSZ
Maximum number of bytes that can be placed in the data portion of any streams message on the system.

nstrpty
System-wide maximum number of streams-based PTYs that are allowed on the system.

streampipes
Force All Pipes to be Streams-Based


?? VME I/O Subsystem Parameters
vmebpn_public_pages
Number of Kernel I/O Space Pages Needed by VME

vmebpn_sockets
Socket Domain AF_VME_LINK is Active (Boolean)

vmebpn_tcp_ip
Maximum Number of DLPI PPAs

vmebpn_tcp_ip_mtu
Maximum PPA transmission unit size in Kbytes

vmebpn_total_jobs
Maximum Number of VME Ports Open Concurrently

vme_io_estimate
Number of 4-Kbyte kernel I/O space pages needed by VME

[Frank Slootweg]

Please specify which type of I/O you are interested in.

If disk then specify the type of filesystem.

If non-disk, then specify the exact type and sub-type of device.

Please also specify whether you are interested in physical or logical limits.

I.e. a simple question, but a complex/impossible answer.

[Tim Sanko]

TQVM

A Lawyer would ask "How big do you want it to be?"

Seriously there wasn't enough information to answer your question in an intelligent manner. Do you mean DISK IO,
ehternet packet size, Memory segment, I need more information and your kernel tuning parms to answer wisely.
also yout FS type if this is for a disk, and your disk layouts to make informed
analysis.

Tim