And now to the list...

On Jul 27, 2012 6:21 AM, "grarpamp" <grarpamp@gmail.com> wrote:
>
> Update: this class of machine just became useless for bitcoin.
> When blk0002.dat was created to store more blocks, all forward
> progress processing blocks turned into losing ground by 20 or so
> a day. Guessing both datfiles were being accessed at once resulting
> in disk based overload. I've not seen any other mentions of crypto
> in this thread so I'm not sure how well new hardware would perform.
> Going shopping I guess.

I doubt the encryption is the problem. I have a much more recent machine (i7 with 8 GiB RAM), and my blockchain is on a (userspace!) encrypted filesystem. However, I do not notice any measurable slowdown from doing so.

You are however using a filesystem (ZFS) that is uses its own filesystem caching implementation to reach some performance, and is known to be very memory-hungry at that. Furthermore, I believe it is known to have performance issues on 32-bit architectures. The bdb backend Bitcoin uses does many I/O operations, and writes them synchronously to disk, killing whatever caching your filesystem provides. For those who run a large database on ZFS, I believe it is advised to put ZFS's intent log on a separate SSD-backed device, to get fast synchronous writes.

That said, some improvememts may be coming. Mike has been working on changing the backend from bdb to leveldb, which may (or may not) result in a very different performance profile on your machine. Also, I've been working on switching the bitcoin block verifier to use a different style database layout ("ultraprune"), which is smaller, faster, and will support pruning. A recent test on my own machine synced the blockchain up to the latest checkpoint in 7 minutes (6 minutes when stored in RAM instead of disk).

--
Pieter