Migrating a node

[Alexey]

I see, that explains a too high memory usage.
You can take a look on:

Information to SNO's regarding ZFS/btrfs vs. ext4 on spinners

I use BTRFS without issues now, but I had to disable future CoW and remove CoW from my existing files. My current BTRFS /etc/fstab settings are: defaults,nofail,noatime,nodiratime,nodatacow,noautodefrag. I ultimately had to disable CoW, shutdown my node, move the data, and copy it back (rewrite without CoW), then restart the node. I also tried a defrag before this (in theory it would allow you to do everything with the node online, but that was essentially locking up my node (watch your RAM u…

and

@Toyoo

btrfs was more than twice slower under all metrics even under the best settings I found (mkfs.btrfs -m single -d single, mount -o nodatacow,noatime,max_inline=0). I suspect that bandwidth.db updates dominate I/O performance there, maybe moving them to flat files—like the orders were moved—would help. But at this point this is only a suspicion and I’m waiting for some other tests to finish to check this as well.

and

-t 300 not enough

Finally finished migration. The difference is clear: I’m barely getting 20 writes per second, when I used to have even 200 on btrfs, when comparing a similar period in terms of a number and size of upload requests. I didn’t expect the difference will be so huge. One thing is that the btrfs partition was accidentally created with metadata in DUP scheme, which probably explains half of the difference. Maybe being log-structured might explain the other half? So while I don’t have hard evidence ag…