Re: performance recommendations

["Pal, Laszlo" <vlad@vlad.hu>]

So,

I'm trying to recover this stuff... this is a CentOS7 based system
running for almost two years. It was never too fast, but did what I
intended to do, but today I've observed very very bad performance on
ls, rm and other complicated commands. Like rm <any single file> takes
forever and in iotop I can see this command is using 50% of i/o
together with btrfs-transacti, so something definitely wrong

I've added ram and cpu to the VM, but it does not help. Now, I'm also
trying to modify fstab to add noatime, autodefrag

In the journal I can see some "free cache file invalid, skip" warnings

Can anyone offer me some help, so at least I can boot the machine
(right now the boot times out on mount task, so I can have either
emergency mode or rescuecd)

Thank you
Laszlo

On Mon, Feb 15, 2021 at 3:53 PM Pal, Laszlo <vlad@vlad.hu> wrote:
>
> Hi,
>
> I'm not sure this is the right place to ask, but let me try :) I have
> a server where I mainly using btrfs because of the builtin compress
> feature. This is a central log server, storing logs from tens of
> thousands devices, using a text files in thousands of directories in
> millions of files.
>
> I've started to think it was not the best idea to choose btrfs for this :)
>
> The performance of this server was always worst than others where I
> don't use btrfs, but I thought this is just because the i/o overhead
> of compression and the not-so-good esx host providing the disk to this
> machine. But now, even rm a single file takes ages, so there is
> something definitely wrong. So, I'm looking for some recommendations
> for such an environment where the data-security functions of btrfs is
> not as important than the performance.
>
> I was searching the net for some comprehensive performance documents
> for months, but I cannot find it so far.
>
> Thank you in advance
> Laszlo