Topic: Low Bitcoin-QT sync -> I have found the bottleneck. Need advices please... (Read 452 times)
October 17, 2017, 09:59:03 AM
If you have a lot of RAM available, you can set -dbcache= is an amount of RAM in MB that you would like to dedicate to the database cache (note that this is not the only RAM usage by Bitcoin Core). This generally helps sync faster as the database will not need to be flushed to the disk as often so there is less disk IO to slow you down. Blocks will still need to be written to disk and that will likely still be a bottleneck, but the database won't be written as often and that writing is usually the bottleneck because of some things that LevelDB does during flushing.
October 17, 2017, 08:59:17 AM
- My Bitcoin QT is fully synced... I update it each 2 days approximately, and this sync takes 1 full hour...
I used to do this too, until I installed more RAM. Now I just keep it running, it's always synced, and doesn't take much resources. 
October 17, 2017, 07:45:24 AM
I don't really know where is the problem. Here are the facts :
- My Bitcoin QT is fully synced... I update it each 2 days approximately, and this sync takes 1 full hour... i expected a better speed, that's why I posted here.
- I have tested 2 HDD, and the problem stills the same. Both are Seagate Barracuda and have approximately 4 years. The first has 1 To, the other has 2 To.
- Slow reading only happen for Bitcoin QT (if I copy paste a big folder of, let's say, 10 go with multiple files, the average speed is 30 Mo/sec, with a min at 3 Mo/sec and a max at 120 Mo/sec).
- Both HDD haven't any issue, tested with GSmartControl.
- I'm not only interested in QT wallets, for security reasons and, btw, for fees reasons.
I'll test with another HDD, a Western Digital Green 2 To (4 years old too) and see if it performs better.
- My Bitcoin QT is fully synced... I update it each 2 days approximately, and this sync takes 1 full hour... i expected a better speed, that's why I posted here.
- I have tested 2 HDD, and the problem stills the same. Both are Seagate Barracuda and have approximately 4 years. The first has 1 To, the other has 2 To.
- Slow reading only happen for Bitcoin QT (if I copy paste a big folder of, let's say, 10 go with multiple files, the average speed is 30 Mo/sec, with a min at 3 Mo/sec and a max at 120 Mo/sec).
- Both HDD haven't any issue, tested with GSmartControl.
- I'm not only interested in QT wallets, for security reasons and, btw, for fees reasons.
I'll test with another HDD, a Western Digital Green 2 To (4 years old too) and see if it performs better.
October 16, 2017, 02:43:28 PM
Actuall you don't really need a SSD to run the Core client. But 700 kb of reading is very very slow. You should check your Hard drive.
It may be about to die. A standard HDD should easily be able to guarantee a read/write speed of 20++ mb/s without making your system slow.
You're talking about sequential reading, Bitcoin Core requires random access, which has a much lower total throughput. When it comes to random access, a SSD runs circles around a HDD. It may be about to die. A standard HDD should easily be able to guarantee a read/write speed of 20++ mb/s without making your system slow.
October 16, 2017, 01:44:35 PM
Actuall you don't really need a SSD to run the Core client. But 700 kb of reading is very very slow. You should check your Hard drive.
It may be about to die. A standard HDD should easily be able to guarantee a read/write speed of 20++ mb/s without making your system slow.
I would recommend to download a HDD checking tool and read out your S.M.A.R.T values (https://en.wikipedia.org/wiki/S.M.A.R.T.).
And if your HDD is fine.. you could just wait until it synced 1 time (taking long time) but afterwards you wont have to wait that long to be up to date.
Im not a fan of SSHD. I dont like the concept. I would stay with HDD (at least one which has normal read/write speed)
It may be about to die. A standard HDD should easily be able to guarantee a read/write speed of 20++ mb/s without making your system slow.
I would recommend to download a HDD checking tool and read out your S.M.A.R.T values (https://en.wikipedia.org/wiki/S.M.A.R.T.).
And if your HDD is fine.. you could just wait until it synced 1 time (taking long time) but afterwards you wont have to wait that long to be up to date.
Im not a fan of SSHD. I dont like the concept. I would stay with HDD (at least one which has normal read/write speed)
October 16, 2017, 12:38:36 PM
Hello there,
I have actually all my wallets, included Bitcoin QT, on a Seagate Barracuda 5200 tr/min (2 To)... and it seems my long sync time for the bitcoin client is due to it (my hard drive is at 98-100%, at an average of 700 ko of reading).
In order to solve this problem, I wonder if a SSHD can do a better job... because I don't want to spend 1000 bucks in a 1 TB SSD. Does someone already tried an SSHD specifically for the bitcoin QT client? Does it help a lot?
Regards.
I have actually all my wallets, included Bitcoin QT, on a Seagate Barracuda 5200 tr/min (2 To)... and it seems my long sync time for the bitcoin client is due to it (my hard drive is at 98-100%, at an average of 700 ko of reading).
In order to solve this problem, I wonder if a SSHD can do a better job... because I don't want to spend 1000 bucks in a 1 TB SSD. Does someone already tried an SSHD specifically for the bitcoin QT client? Does it help a lot?
Regards.
By sshd do you mean a hybrid drive? If so, I'm not sure that'll fix anything unless you try to prune it to the solid state part.
Is this the first time you've used the drive. You could try troubleshooting tools on the drive and do other things like defragmentation (If it isn't new).
October 16, 2017, 11:42:34 AM
SSD is much faster for anything that has to access your disk a lot. It'll improve your sync time.
But, that's only a one-time thing, my fully synced Bitcoin Core runs fine from HDD. If you rescan or import private keys a lot, you'll still benefit from a faster drive.
Edit: after reading jackg's addition, I realize I misread SSHD for SSD. Sorry, in that case I don't think it matters. Just give it time, be patient, and have your full Bitcoin Core.
But, that's only a one-time thing, my fully synced Bitcoin Core runs fine from HDD. If you rescan or import private keys a lot, you'll still benefit from a faster drive.
Edit: after reading jackg's addition, I realize I misread SSHD for SSD. Sorry, in that case I don't think it matters. Just give it time, be patient, and have your full Bitcoin Core.
October 16, 2017, 10:04:31 AM
Hello there,
I have actually all my wallets, included Bitcoin QT, on a Seagate Barracuda 5200 tr/min (2 To)... and it seems my long sync time for the bitcoin client is due to it (my hard drive is at 98-100%, at an average of 700 ko of reading).
In order to solve this problem, I wonder if a SSHD can do a better job... because I don't want to spend 1000 bucks in a 1 TB SSD. Does someone already tried an SSHD specifically for the bitcoin QT client? Does it help a lot?
Regards.
I have actually all my wallets, included Bitcoin QT, on a Seagate Barracuda 5200 tr/min (2 To)... and it seems my long sync time for the bitcoin client is due to it (my hard drive is at 98-100%, at an average of 700 ko of reading).
In order to solve this problem, I wonder if a SSHD can do a better job... because I don't want to spend 1000 bucks in a 1 TB SSD. Does someone already tried an SSHD specifically for the bitcoin QT client? Does it help a lot?
Regards.
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