aio_iosize_max man page on HP-UX

Man page or keyword search:  
man Server   10987 pages
apropos Keyword Search (all sections)
Output format
HP-UX logo
[printable version]

aio_iosize_max(5)					     aio_iosize_max(5)

       aio_iosize_max  -  maximum  size of any asynchronous I/O in an lio_lis‐
       tio(), aio_read(), or aio_write() call

   Allowed values
   Recommended values
       This tunable places a limit on the size (in bytes) of asynchronous  I/O
       operations  that	 can  be  issued  with	lio_listio(2), aio_read(2), or
       aio_write(2).  It is useful for limiting the amount of memory that  can
       be consumed by asynchronous I/O operations.

       When this tunable is at its default value of 0, it has no effect.

       When this tunable is set to a positive number, all asynchronous I/Os of
       size larger than that number will fail with Although this tunable  will
       affect  all  applications  that	use  asynchronous I/O, its most common
       usage is in conjunction with This combination is	 useful	 for  limiting
       the  system  resources  that  can  be  used  by	applications  that use

   Who Is Expected to Change This Tunable?
       System administrators that run applications requiring  heavy  usage  of
       AIO to disks or filesystems.

   Restrictions on Changing
       This  tunable is dynamic.  Changes to to this tunable take effect imme‐
       diately after the change.  All processes on the system will be  immedi‐
       ately impacted, including processes already running.

   When Should the Value of This Tunable Be Raised?
       should  be  raised for applications requiring heavy use of asynchronous

   What Are the Side Effects of Raising the Value of This Tunable?
       When raising the value of this tunable from 0 to	 any  positive	value,
       the limit defined by this tunable will begin to be enforced.  (See

       However,	 once  this  tunable  is  a positive value, the only effect of
       raising it further is that larger I/Os can be issued  by	 applications.
       Limits  such as will continue to be enforced after this tunable is set.
       (Unless aio_proc_max(5) has already been used to disable them)

   When Should the Value of This Tunable Be Lowered?
       should be lowered when POSIX AIO performance is acceptable but there is
       concern about buggy or malicious applications issuing excessively large
       I/Os that tie up system resources.  When this tunable is non-zero,  its
       value  should  never  be	 lower	than  the minimum I/O size required by
       trusted applications running on the system.

   What Are the Side Effects of Lowering the Value of This Tunable?
       As long as it remains a positive value, lowering the value of this tun‐
       able  simply  reduces  the  maximum possible size of asynchronous I/Os.
       When this tunable is set to 0, it will cease to have an effect, and  no
       limits will be imposed on the size of individual asynchronous I/Os.

   What Other Tunables Should Be Changed at the Same Time as This One?
       No other tunables need to be changed at the same time as this one.

       However,	 the  most common usage is for this tunable to be used in con‐
       junction with In this way, the total memory usage of all processes that
       use aio_reap(2) is constrained by the quantity:

       All HP-UX kernel tunable parameters are release specific.  This parame‐
       ter may be removed or have its meaning changed in  future  releases  of

       Installation of optional kernel software, from HP or other vendors, may
       cause changes to tunable parameter values.   After  installation,  some
       tunable	parameters may no longer be at the default or recommended val‐
       ues.  For information about the effects of installation on tunable val‐
       ues, consult the documentation for the kernel software being installed.
       For  information	 about	optional  kernel  software  that  was  factory
       installed on your system, see at

       was developed by HP.

       kctune(1M),  sam(1M), gettune(2), settune(2), aio_reap(2), aio_read(2),
       aio_write(2), lio_listio(2), aio_physmem_pct(5), aio_proc_max(5).

			   Tunable Kernel Parameters	     aio_iosize_max(5)

List of man pages available for HP-UX

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net