HP-UX Ramdisk Release Notes HP-UX 11i v2 HP Part Number: 5992-4656 Published: June 2008
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Table of Contents 1 HP-UX Ramdisk Release Notes.....................................................................................................5 Announcement.....................................................................................................................6 Features and Benefits............................................................................................................6 Features...........................................................................................
List of Tables 1-1 4 Ramdisk Related Documents......................................................................................
1 HP-UX Ramdisk Release Notes This document discusses the most recent product information on HP-UX Ramdisk that is supported on the HP-UX 11i v2 operating system.
Announcement Ramdisk is emulation of disk in system memory. Accessing files on a Ramdisk is much faster than accessing files on a real disk. This is especially useful for applications that use intermediate temporary files frequently. Applications can access files on a Ramdisk in a way that is similar to accessing files on a hard disk. However, the data saved on the Ramdisk is not persistent across reboots. The patches, PHKL_37170 and PHCO_37169 enable you to create a swappable disk or a non-swappable disk.
Benefits Ramdisk offers the following benefit: • • Can operate at memory speed, which provides very high throughput. Applications that require high throughput can use this feature. The swappable Ramdisk volume size can be bigger than physical system memory. Installing Ramdisk The system memory can be configured for use as a Ramdisk after installing the required patches on the system.
-s Specifies the size of the Ramdisk volume To delete a Ramdisk instance, enter the following command at the HP-UX command prompt: $ ramutil -d -v volume_number Where: -d -v Deletes a Ramdisk volume Associates a volume number with the Ramdisk For more information about using the command, see the ramutil(1M) manpage.
Limitations The following limitations are encountered while using the Ramdisk: • • • • The Boot, root, swap, and dump configurations are not supported on Ramdisk. Also, LVM devices configured for Boot, root, swap, and dump must not have Ramdisk. Non-swappable Ramdisk can be created upto a maximum size of 4GB or equal to the available size of the system memory. Therefore, the super user must check the system memory size before creating non-swappable Ramdisk.
• • The use of Ramdisk as a spare disk in LVM mirror configurations is not supported. Ramdisk is not tested/certified with Vpars / HPVM. Related Information Table 1-1 lists the related documents available for Ramdisk users. Table 1-1 Ramdisk Related Documents Description Location Manpages ramutil(1M), diskinfo(1M), ioscan(1M), and ramdisc(1M) White Paper http://www.docs.hp.com Localization The Ramdisk documentation is available in English language only.
