IOPageLockLimit unit

Manage File System Caching Memory (Windows NT/2000) Popular
Windows will normally limit the amount of RAM that can be locked for file system operations. This setting allows you to modify the automatic value.

Open your registry and find the key below.
Create a new DWORD value named 'IoPageLockLimit' if it does not already exist. Set the value to equal the maximum number of Kbytes to be allocated to I/O operations as per the table below:


RAM       IoPageLockLimit
(MB)       Decimal    Hex
4           4096     1000
8           8192     2000
16         16384     4000
32         32768     8000
64         65536    10000

As with all performance related changes, get a baseline measurement using performance monitor and then make your changes in small increments and retest the performance after each change.

Home > Windows > File System > Caching and Memory

Manage File System Caching Memory (Windows NT/2000) Popular
Windows will normally limit the amount of RAM that can be locked for file system operations. This setting allows you to modify the automatic value.

 This tweak can be easily applied using WinGuides Tweak Manager.
Download a free trial now!

Open your registry and find the key below.
Create a new DWORD value named 'IoPageLockLimit' if it does not already exist. Set the value to equal the maximum number of Kbytes to be allocated to I/O operations as per the table below:


RAM       IoPageLockLimit
(MB)       Decimal    Hex
4           4096     1000
8           8192     2000
16         16384     4000
32         32768     8000
64         65536    10000

As with all performance related changes, get a baseline measurement using performance monitor and then make your changes in small increments and retest the performance after each change.



 
     
  (Default) REG_SZ (value not set)  
  IoPageLockLimit REG_DWORD 0x00000000 (0)  
 
 HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session ...  
 
Registry Settings
System Key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\
Memory Management]
Value Name: IoPageLockLimit
Data Type: REG_DWORD (DWORD Value)
Value Data: 0 = default
 
 http://www.winguides.com/registry/display.php/55/

yes, i've already found and read it on the ms web...
if it is in bytes and i want to set 64MB, i have to enter 0x04000000

because i've already found a lot of links with iopagelock in kilobytes and if i want to set 64MB, i have to enter 0x00010000
http://www.winguides.com/registry/display.php/55/
http://www.winpage.info/pages/Win2000/tuning.php4

Advice me pls just a number i need to enter, or which number i should use for sql server with 2GB RAM?

russians entered bytes...

А в приведенной вырезке из доки по оптимизации ХР (полный вариант на http://xpsite.net/optim/index.php?id=8sec) советуют использовать значения от 8MB до 16MB, что соответствует 8388608 (DEC) и 16777216 (DEC) или 800000(HEX) и 1000000 (HEX)
http://forums.ag.ru/?action=display&board=gothic&num=1073080768&start=225

Эта настройка будет очень полезна в случае запуска XP в качестве сервера. Это позволит увеличить производительность во время операций передачи данных. Для этого Вам необходимо создать REG_DWORD ключ IOPageLockLimit. Значение ключа указывается в байтах. Максимальное значение 512KB. Пользователи, которые уже попробовали настроить максимальную производительность, советуют использовать значение ключа в диапазоне 8 – 16MB. Для того, что бы перевести значение мегабайт в байты необходимо выполнить следующие вычисления: необходимо число MB * 1024 * 1024. Так, для 12MB необходимо 12 * 1024 * 1024 = 12582912. Эту настройку можно использовать только в случае использования 256+MB RAM

:((( sorry ... rushian alphabet...

Stop a minute

Improve usage of Physical RAM and caches to significantly improve system performance.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management]

DisablePagingExecutive=1 Will load your core Win files into system RAM and keep them there. Use this tweak if you have 512MB RAM or more.

LargeSystemCache=0 For 512MB RAM (OR MORE) -  set to 1 for potential performance improvement.

Note that data corruption may occur if the Large System Cache feature is enabled in Windows . If you have more than 512MB of RAM, a large NTFS disk or multiple large volumes (60-100 gigabyte hard drives possibly in RAID arrays), and/or AGP graphics with large AGP resource requirements (AGP aperture greater than default) then you will get hard drive corruption. Don't enable Large System Cache in these circumstances, i.e use LargeSystemCache=0.

DONT mess with lock limits they are in the registry because historically there was a cap set at 512Mb (hence you can only find up to that amount (and if you hunted enough you would find a value that worked for 768Mb)

still not clear..
1. i thought iopagelocklimit is the amount of cache in ram reserved for io operations..?
2. i already have!! 2GB RAM & 150GB NTFS RAID5 & DisablePagingExecutive=1 & LargeSystemCache=1 , so i will get hdd corruption??

i've just wanted increase io cache from default (512kB) to 64MB...

Pete pls just 2 questions:
1. is iopagelocklimit amount of ram reserved for io operations?
2. what is correct value for iopagelocklimit to allocate 64MB?
Thanks a lot. Kuko