doc: add reduce-memory.md #16339

fanquake commented at 1:18 AM on July 5, 2019: member

Following some discussion in https://github.com/bitcoin-core/docs/issues/50, this adds Wladimir's reducing bitcoind memory usage gist to /doc.

The conclusion seemed to be that if the main repo already has reduce-traffic.md, then we could also add reduce-memory.md.

fanquake added the label Docs on Jul 5, 2019

fanquake force-pushed on Jul 5, 2019

in doc/reduce-memory.md:11 in 341e5a673a outdated

   6 | +## In-memory caches
   7 | +
   8 | +The size of some in-memory caches can be reduced. As caches trade off memory usage for performance, reducing these usually have a negative effect on performance.
   9 | +
  10 | +- `-dbcache=<n>` - the UTXO database cache size, this defaults to `450` (since 0.14.1). The unit is MiB (1024)
  11 | +  - Before 0.11.0 the computation here was off, so a factor of about five times more memory was used than specified.

hebasto commented at 2:38 AM on July 5, 2019:

Could pre-0.11 versions mention be removed?

in doc/reduce-memory.md:13 in 341e5a673a outdated

   8 | +The size of some in-memory caches can be reduced. As caches trade off memory usage for performance, reducing these usually have a negative effect on performance.
   9 | +
  10 | +- `-dbcache=<n>` - the UTXO database cache size, this defaults to `450` (since 0.14.1). The unit is MiB (1024)
  11 | +  - Before 0.11.0 the computation here was off, so a factor of about five times more memory was used than specified.
  12 | +  - The minimum value for `-dbcache` is 4.
  13 | +  - A lower dbcache makes initial sync time much longer. After the initial sync, the effect is less pronounced for most use-cases, unless fast validation of blocks is important, such as for mining.

hebasto commented at 2:40 AM on July 5, 2019:

Could dbcache word be code-styled i.e. -dbcache?

in doc/reduce-memory.md:18 in 341e5a673a outdated

  13 | +  - A lower dbcache makes initial sync time much longer. After the initial sync, the effect is less pronounced for most use-cases, unless fast validation of blocks is important, such as for mining.
  14 | +
  15 | +## Memory pool
  16 | +
  17 | +- To protect against mempool flooding set `minrelaytxfee=0.00005` and `limitfreerelay=5`. See the 0.11.0 release notes at https://github.com/bitcoin/bitcoin/blob/v0.11.0/doc/release-notes.md#transaction-flooding . **This is no longer necessary for 0.12.0 and above**.
  18 | +

hebasto commented at 2:42 AM on July 5, 2019:

Could pre-0.12 versions mention be removed?

hebasto commented at 2:44 AM on July 5, 2019: member

Approach ACK 341e5a673a9dd3ef9d225e49362a600d7bd4f213

practicalswift commented at 2:58 PM on July 5, 2019: contributor

utACK 341e5a673a9dd3ef9d225e49362a600d7bd4f213 modulo @hebasto's nits :-)

flack commented at 6:42 PM on July 5, 2019: contributor

Shouldn't this be linked to from README.md?

docs: add reduce-memory.md

Co-Authored-By: Wladimir J. van der Laan <laanwj@gmail.com>

64b27c46e4

fanquake force-pushed on Jul 6, 2019

fanquake commented at 2:47 AM on July 6, 2019: member

Have removed the old version mentions, as well as fixed some styling and wording.

Shouldn't this be linked to from README.md?

Added a link from /doc/README.md

practicalswift commented at 5:56 AM on July 6, 2019: contributor

ACK 64b27c46e4c21fc7902a69d8ddb6791ef417c4af

hebasto commented at 6:07 AM on July 6, 2019: member

ACK 64b27c46e4c21fc7902a69d8ddb6791ef417c4af, I have reviewed the changes and they look OK, I agree they can be merged. Also a link from /doc/README.md has been tested.

in doc/reduce-memory.md:9 in 64b27c46e4

   0 | @@ -0,0 +1,49 @@
   1 | +# Reduce Memory
   2 | +
   3 | +There are a few parameters that can be dialed down to reduce the memory usage of `bitcoind`. This can be useful on embedded systems or small VPSes.
   4 | +
   5 | +## In-memory caches
   6 | +
   7 | +The size of some in-memory caches can be reduced. As caches trade off memory usage for performance, reducing these will usually have a negative effect on performance.
   8 | +
   9 | +- `-dbcache=<n>` - the UTXO database cache size, this defaults to `450`. The unit is MiB (1024).

promag commented at 3:02 PM on July 6, 2019:

defaults to `450 MiB` (1 MiB = 1024 bytes).

fanquake commented at 12:36 AM on July 8, 2019:

Thanks. However given the 4 ACKs I'm going to merge this.

promag commented at 3:05 PM on July 6, 2019: member

Noice ACK, just had a quick look and also didn't confirm since x.x.x versions - not sure if it's relevant here.

jonasschnelli commented at 9:45 PM on July 7, 2019: contributor

Good idea! ACK 64b27c46e4c21fc7902a69d8ddb6791ef417c4af

fanquake merged this on Jul 8, 2019

fanquake closed this on Jul 8, 2019

fanquake referenced this in commit 2b465195e0 on Jul 8, 2019

fanquake deleted the branch on Jul 8, 2019

jnewbery commented at 9:05 AM on July 8, 2019: member

ACK 64b27c46e4c21fc7902a69d8ddb6791ef417c4af

Thanks @laanwj and @fanquake for adding this.

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ikeedge commented at 3:09 AM on July 3, 2021: none

M

fanquake locked this on Jul 5, 2021