Speed of Block Storage
We just added a Block Storage Volume but are wondering about the speed.
First when we synced our data using rsync it took around 75 minutes to sync 149GB.
Even doing a simple
du of the directory takes forever compared to the server storage:
The block storage is mounted on
/home/test/media and the previous directory has been renamed to
[email protected]:/home/test# time du media -hsc 150G media 150G total real 4m21.515s user 0m1.432s sys 0m8.336s [email protected]:/home/test# time du media_old -hsc 149G media_old 149G total real 0m34.800s user 0m1.085s sys 0m7.484s
That's an increase of about 770%, I was expecting an increase due to the fact it's external storage but 770% seems excessive.
While it’s expected to see a performance difference between internal and Block Storage, especially given the difference between the SSD storage Linode's have and the NVMe disks that make up Block Storage, the gap here seems a bit large. Typically you can expect up to 150MB/s and up to 5K IOPS on Block Storage volumes. The rsync results you mentioned seem to be clocking in at about 41.38MB/s, although there are some other factors that could be at play here. Was this data rsync’d locally from a directory to the Volume? Or was this from another Linode or a remote server?
Additionally, while the configuration of our Block Storage service allows for fast write speeds, read speeds can be often be somewhat slower. This may account for the larger difference you’re seeing in ‘du’.
If you’d like to open a Support Ticket, we’ll be happy to continue troubleshooting and dig a little deeper into this with you. The output of the following commands would be really helpful to us:
# This will give us a benchmark for write speeds
dd if=/dev/zero of=blockstorage.test bs=4M count=4000
# This will give us a benchmark for read speeds
dd if=blockstorage.test of=/tmp/blockstorage.test bs=4M
# This will give us an idea of general system stats
iostat 1 10
Thanks for the quick response.
The rsync was locally. The block storage was added to the server and the directory was synced to the directory the block storage was mounted on.
I'll open a support ticket and add the output of the benchmarks as well.