Tutorial: RAMDISK in DSM

[smileyworld]

@amikot was asking me how to implement a RAMDISK in DSM and I found this guide. So many thanks to mark and as usual I don't accept any liability for any data loss or damage caused by using this tutorial(s).

 

I wrote a little script which adapts to your environment and asks if you would like to

• specify the amount of RAM in percent or GB
• the amount of RAM which should be used for the Ramdisk
• an existing folder where your RAMDISK should be created. E.g. /volume1/ramdisk

 

You have to save the following lines as "create_ramdisk.sh" run it, answer the questions and add two tasks (which is demonstrated in the gif) to the task scheduler:

 

#!/bin/bash
echo Do you want to specify the amount of RAM, which should be used for the RAMDISK, in percent or in GB?
read ram_unit

if [ $ram_unit = 'percent' ]; then
echo Please type in the amount of RAM which should be used. E.g. 2 for 2GB or 2 percent depending on your former choice
read ram_amount

elif [ $ram_unit = 'GB' ]; then
read ram_amount

else
echo "Please enter percent or GB"
read ram_unit
echo Please type in the amount of RAM which should be used. E.g. 2 for 2GB or 2 percent depending on your former choice
read ram_amount
fi

echo Please type in an existing folder where your RAMDISK should be created. E.g. /volume1/ramdisk
read path

mkdir $path/ramdisk
mkdir $path/ramdisk-local

if [ $ram_unit = 'percent' ]; then

echo "#!/bin/sh
mount -t tmpfs -o size="$ram_amount"% ramdisk $path/ramdisk
sleep 1
rsync -ahW --no-compress  $path/ramdisk-local/  $path">| $path/mount-ramdisk.sh

else

echo "#!/bin/sh
mount -t tmpfs -o size="$ram_amount"G ramdisk $path/ramdisk
sleep 1
rsync -ahW --no-compress  $path/ramdisk-local/  $path">| $path/mount-ramdisk.sh

fi

echo "#!/bin/sh
rsync -ahW --no-compress --delete $path/ramdisk/ $path/ramdisk-local/">| $path/sync-ramdisk.sh

 

• one for mounting the ramdisk when booting your NAS
• the second is a rsync job to copy the files from the ramdisk to a ssd/hdd

 

 

 

here is the command for listing your ramdisk after creating and mounting it

df | grep "ramdisk"

 

 

here is the command for testing speed but keep in mind to adapt your path and RAM amount to your environment

sudo dd if=/dev/zero of=/volume1/ramdisk/ramdisk/test1.img bs=30G count=1 oflag=dsync

 

For anyone wondering:

ramdisk refers to the content which is temporarily saved in your ram

ramdisk-local is the copied content from the ramdisk to your hdd/ssd

 

Unmounting the ramdisk is possible via rebooting your NAS or running this command:

umount ramdisk

 

Edited March 21, 2021 by smileyworld
extending