I have a production server, recently, I have seen server becomes slow sometimes, and SSH is slow, and once get into the terminal, even press ENTER is slow.
When the server is OK, I checked the memory usage and CPU, CPU looks fine, RAM looks fine except SWAP is 100% used. I googled it seems SWAP should not be 100% used, maybe 50%.
So I would like to increase the SWAP size. But since this is a production server, and it has soft RAID1 configured, so I don’t want to mess it up until I am sure it is absolutely correct.
Here are the server configs:
CPU is E3-1245-V2, 32G RAM, 3x2T HDD
top command result:
top - 05:33:54 up 2 days, 13:45, 1 user, load average: 2.43, 2.43, 2.50 Tasks: 243 total, 1 running, 165 sleeping, 0 stopped, 0 zombie %Cpu(s): 28.4 us, 0.6 sy, 0.0 ni, 69.0 id, 1.7 wa, 0.0 hi, 0.2 si, 0.0 st KiB Mem : 32893852 total, 278960 free, 28153624 used, 4461268 buff/cache KiB Swap: 1569780 total, 0 free, 1569780 used. 4226648 avail Mem
df -h result:
Filesystem Size Used Avail Use% Mounted on udev 16G 0 16G 0% /dev tmpfs 3.2G 1.5M 3.2G 1% /run /dev/md3 20G 7.4G 11G 41% / tmpfs 16G 0 16G 0% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 16G 0 16G 0% /sys/fs/cgroup /dev/md2 487M 148M 310M 33% /boot /dev/md4 1.8T 536G 1.2T 32% /home tmpfs 3.2G 0 3.2G 0% /run/user/1000
cat /proc/mdstat result:
Personalities : (raid1) (raid0) (raid6) (raid5) (raid4) (linear) (multipath) (raid10) md4 : active raid1 sdb4(1) sdc4(2) sda4(0) 1931981760 blocks (3/3) (UUU) bitmap: 5/15 pages (20KB), 65536KB chunk md2 : active raid1 sda2(0) sdb2(1) sdc2(2) 523200 blocks (3/3) (UUU) md3 : active raid1 sda3(0) sdb3(1) sdc3(2) 20478912 blocks (3/3) (UUU) unused devices: <none>
sudo swapon --show result:
NAME TYPE SIZE USED PRIO /dev/sdb5 partition 511M 511M -2 /dev/sdc5 partition 511M 511M -3 /dev/sda5 partition 511M 511M -4
I was going to follow this tutorial https://linuxize.com/post/how-to-add-swap-space-on-ubuntu-18-04/ but I am afraid since I have soft raid1 here, I am not sure if the instructions above still apply, or it should work.