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Memory file system

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denisl

Technical User
Jun 18, 2001
36
US
I'm trying to create a memory filesystem where I can keep some frequently accessed files.

I can't figure out how to create a file system in memory.
Can someone give me the command to create a fs in memory?
Thanks!
 
You could do it with a cachefs, but it will give you no benefit. When you are going to read a file into a program AIX will automatically cache it until you need the memory for something else. After your initial request of the file you should see no performance improvement. You will only see an improvement if the files are accessed through NFS from another server.


See cachefs.

1. You cannot cache the / (root) or /usr file systems.
2. You can mount only file systems that are shared. (See the exportfs command.)
3. There is no performance gain in caching a local Journaled File System (JFS) disk file system.
 
hello,

Have a look at the mkramdisk command, to create a RAM filesystem. Basically the usage is the following :

mkramdisk 40000 (40000 512 bytes blocks, eg 40MB)
mkfs -V jfs /dev/ramdisk0
mkdir /ramdisk0 mount -V jfs -o nointegrity /dev/ramdisk0 /ramdisk0


If I remember correctly, note that in AIX 5.1 you are limited to 8 ramdisk of 2 GB max.

regards
 
Hi denisl,
I am curious as to why you are doing this. I really dont know much about it, so please dont take my question the wrong way. I am just wondering how you think a memory file system would be helpful to you? Never know, maybe something I could use.
 
Well I did this to create a temp oracle index on and I worked a treat.......

--
| Mike Nixon
| Unix Admin
|
----------------------------
 
Addition to Letis' post.
Note : RAM disks are removed when the machine is rebooted.
 
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