Ramdisk Difference between Linux OS and Sybase?

[Former Member]

Linux provide ramdisk, Sybase 15.x also provide ramdisk. What's the different between Linux and Sybase?

A few questions:

1. Set up ramdisk at OS level or in Sybase, any performance disk?

2. If setup ramdisk within Sybase, it will consume 'Max Memory'?

3. Ramdisk and data cache, which has better performance?

4. If ramdisk available for ASE 12.5? I checked document, and can't find out info.

[former_member188883]

Hi Kent,

Ramdisk is an area of random-access memory (RAM) configured by a utility program to emulate a hard disk drive. Data stored in a RAM disk can be accessed more quickly than data stored on a disk drive, but this data is erased whenever you turn off or reboot the computer.

A ramdisk implementation will still perform IO, meaning context switches in ASE, handing over the request to the OS, etc, and will still require logging and cache management. You will also need twice the memory (for the ramdisk itself, and for the ASE data cache)

Ramdisk is supported for Sybase 12.5 as well.

Data cache is always faster than Ramdisk.

More information in below links

SAP Sybase Forums - ASE - General Discussion - ASE 15.5 IMDB vs ramdisk/tmpfs

SAP Sybase Forums - ASE - Linux - Problem with ASE 12.5.0.3 on RHEL 3.0 and tempdb on ramdisk

Hope this helps.

Regards,

Deepak Kori