ramdisks [a solution]

[Mike Wright]

Bill Davidsen wrote:
> Mike Wright wrote:
>> I came up with a solution that uses LVM and it works a *charm*, 
>> albeit, probably because of large block sizes relative to the 16M size 
>> of the ramdisks, seems inefficient (costs 25% each).  Maybe I can tune 
>> these and get better.
>>
>> pvcreate /dev/ram15
>> pvcreate /dev/ram14
>> pvcreate /dev/ram13
>> pvcreate /dev/ram12
>>
>> vgcreate my36Mdisk /dev/ram15 /dev/ram14 /dev/ram13
>> vgcreate my12Mdisk /dev/ram/12
>>
>> lvcreate -n myRamDisk1 -L 36M my36Mdisk
>> lvcreate -n myRamDisk2 -L 12M my12Mdisk
>>
> Wow that sounds complex, why not just make the ramdisks larger? Just use 
> the boot parameter which sets that:
>   ramdisk_size=N
> where N is the size in kilobytes, so for 256M you specify 262144.
> 

Thanks for that advice.

I ended up making the ramdisks smaller which gave me greater 
granularity.  Then when the volume groups were created I specified 64K 
extents instead of the default 16M.  That gave two benefits: there was 
almost no wasted space in the VG, and the data that I copied over used 
less than half of the space of the original.

:m)