Ivan Rakov created IGNITE-5884:
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Summary: Change default pageSize of page memory to 4KB
Key: IGNITE-5884
URL: https://issues.apache.org/jira/browse/IGNITE-5884
Project: Ignite
Issue Type: Improvement
Components: persistence
Reporter: Ivan Rakov
Fix For: 2.2
Checkpoint write speed is suboptimal with default 2K page on most UNIX-driven
enviroments with SSD disk. There are several reasons for this:
1) Page size of linux page cache is 4k by default on most kernels (you can
check yours by "getconf PAGE_SIZE" command). With 2k random writes
vm.dirty_ratio threshold is reached two times faster than with 4k random writes.
2) Most SSD manufacturers don't reveal actual disk page size, but they
recommend to write at least 4k at once. Also, 4k blocks are used during
benchmarking SSD random writes. Related question:
https://superuser.com/questions/1168014/nvme-ssd-why-is-4k-writing-faster-than-reading
I've prepared a checkpoint emulation benchmark (code and results attached). Run
on production-level hardware (CentOS, 100 GB RAM, total LFS size is 100GB,
vm.dirty_ratio=10) showed that checkpointing with 4k pages is much more
efficient than with 2k.
*Important: backwards compatibility must be ensured with LFS files created with
old 2k default page size.*
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