I think you will have to do the science there, it will be dependent on
thousands of factors like size of OSD, WAL, DB, placement of them,
size of incoming data if it is many small ops or few large ones and so
on. I don't think any one single answer there would work out for many
cases.
Most of us
OK. How much data will be written to the WAL and elsewhere?
On Mon, Jan 30, 2023 at 3:17 PM Janne Johansson wrote:
> > I'm concerned with the potential increased NVME wear. Assuming writes of
> multiples of the block size, when I write 1GB of data to the CephFS, how
> much data is written to
> I'm concerned with the potential increased NVME wear. Assuming writes of
> multiples of the block size, when I write 1GB of data to the CephFS, how much
> data is written to the disks?
In that case, repl=3 will write 1GB to three PGs. EC 8+3 would write
125M (ie, 1/8 of a GB) to 11 (8+3)
Dear Janne,
I'm concerned with the potential increased NVME wear. Assuming writes of
multiples of the block size, when I write 1GB of data to the CephFS, how
much data is written to the disks?
Best wishes,
Manuel
On Mon, Jan 30, 2023 at 2:25 PM Janne Johansson wrote:
> > is there information
> is there information available anywhere about the write amplification for
> CephFS? I found quite some material on write amplification of VMs using
> journaled file system on top of RBD but nothing as it relates to CephFS?
>
> From my understanding I would expect the following:
>
> - for X-rep,
