AIX > Storage > Disk

AIX Makes Using RAM Easy

Using the mkramdisk command can create high-speed I/O


 

One of the most common concerns for system administrators is maximizing disk performance. The AIX command mkramdisk is ideal for producing very high speed I/O by letting the memory do all the work.

Database administrators are well aware of the benefits of keeping frequently accessed data in memory in order to reduce the need to retrieve that data from disk. The AIX mkramdisk command allows system administrators to create memory-resident file systems. The performance benefits of using RAM disk can be astonishing. The unload of a large TSM database was reduced from 40 hours on SAN disks down to 10 minutes using RAM disk.

Forgotten memory

If RAM disk is so spectacularly fast, why is it one of AIX’s best kept secrets? Two good reasons spring to mind. First, most OSs started out with RAM measured in megabytes, not gigabytes. That meant using large chunks of memory for file systems– -or anything that might be memory-hungry–-was always avoided. The second reason is RAM disk doesn’t survive a reboot, and system outages were much more common 20 years ago. Many servers had scheduled reboots every week, “just to clear out the cobwebs.”

Although the mkramdisk command has been around since AIX 4.3, it’s only now starting to be appreciated for the powerful tool that it is. As servers today have greater memory allocations, and with OS outages greatly reduced if not completely eliminated, using RAM disk file systems becomes a very attractive option.

 

Anthony English is an AIX specialist based in Sydney, Australia.



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AIX Makes Using RAM Easy

Using the mkramdisk command can create high-speed I/O

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