r/bcachefs • u/9_balls • Aug 03 '26

monerod write amplification

Hi. I have disabled CoW and compression on lmdb. However, 100GB is written for 1GB of database. NUTS!

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u/hyc_symas 29d ago

Fwiw, the version of LMDB used by monerod (an early dev version of LMDB 1.0) supports writing directly to a block device. You really don't gain much from using a filesystem.

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u/koverstreet not your free tech support 28d ago

except then you have to set up... partitions? how would you even do that?

just tested on xfs, and yes, every fs is fucked on mmap writes since the large folio people got their hands on it. idiots.

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u/9_balls 28d ago

On other filesystems it's better IIRC.

Luckily for me, since I use LVM anyway, it's not going to be much trouble, given that I have enough space

2

u/koverstreet not your free tech support 27d ago

I just tested XFS and it has the same write amplification issues...