when writing to disk and memory being swallowed up

[John Morrison]

Hello,

I'm seeing when I write a large file within a VM linux, I'm also filing up the VM systems memory.

This memory is released when I delete the file.

dd if=/dev/zero of=test1.img bs=512k count=1000000

Is this normal?

Cheers

 

[John Morrison]

proxmox is on the latest version and using ZFS rpool for everything. Can someone at least say why this is the case when writing to disk within the VM. The VM's memory us used up to the size of the file written to disk. Once you reboot the machine or delete the file, the memory is returned back. I have tried different caches, like writeback etc. I'm using raid 10 tripple mirror.

proxmox-ve: 5.2-2 (running kernel: 4.15.18-7-pve)

zpool status rpool
pool: rpool
state: ONLINE
scan: scrub repaired 0B in 0h57m with 0 errors on Sun Oct 14 01:21:03 2018
config:

NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
sda2 ONLINE 0 0 0
sdb2 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
sdc ONLINE 0 0 0
sdd ONLINE 0 0 0
mirror-2 ONLINE 0 0 0
sde ONLINE 0 0 0
sdf ONLINE 0 0 0
mirror-3 ONLINE 0 0 0
sdg ONLINE 0 0 0
sdh ONLINE 0 0 0
logs
nvme-Samsung_SSD_970_EVO_2TB_S464NB0K707684L-part1 ONLINE 0 0 0
cache
nvme0n1p2 ONLINE 0 0 0

 

[LnxBil]

Is this normal?

Yes:

https://www.linuxatemyram.com/

 

[John Morrison]

Well Bil, what a newbie I feel. After all these years..... just seems like something I've never whiteness, or that I've never even opened my eyes to such inappropriate well-seasoned Linux admin behavior