glommer

8 ms·

91.
by glommer 10y ago
Actually, what Avi has demonstrated in this article is that XFS is the only filesystem that executes it mostly asynchronously. Before we got started with the implementation of the I/O Scheduler (which we eventually wanted anyway for
92.
by glommer 11y ago
Cassandra has a row cache that it does not necessarily use. Most of its data sits in the linux page cache. Because the SSTables are mmaped into memory, you can't get rid of that: even if you do use the row cache, you would be at best u
93.
by glommer 11y ago
For network, the kernel is bypasses through dpdk. For disk, the syscalls are there. But they are always async IO with O_DIRECT. So the OS wont cache and buffer anything. So that is what you bypass
94.
by glommer 11y ago
The point of that is to show how efficient a node can be, because that is what is replaced. All the external facing things for scylla is the same as Cassandra. That includes all the ring stuff and all network protocols. So you should expect
95.
by glommer 11y ago
IO is not only a large part. It is the main part. That is why it is important to get it right : scylla for instance does not leave the cache to the OS. It has its own caches for everything. Never blocks on IO or page faults because all IO b
96.
by glommer 11y ago
It doesn't come from the choice of language. It comes from the choice of architecture. C++ is a tiny piece of the puzzle. It would have been hell to implement such an architecture in Java bit this is as far as the language matters.