seastarer

6 ms·

1.
by seastarer 2mo ago
You can try to re-vectorize the code for larger vector size.
2.
by seastarer 4mo ago
It's more correct to use O_DSYNC in addition to O_DIRECT. This adds FUA to the disk write if the disk requires it for durability.
3.
by seastarer 9mo ago
It is actually very cheap if done right. Enterprise SSDs have write-through caches, so an O_DIRECT|O_DSYNC write is sufficient, if you set things up so the filesystem doesn't have to also commit its own logs.
4.
by seastarer 10mo ago
Do these calculations take into account the lengthening of the days due to tidal friction?
5.
by seastarer 2y ago
They should have refused
6.
by seastarer 2y ago
Translating 197 M/mm2 into the dimensions of a square, we get a dimension of 71nm. If we compute the "half-pitch", that's 35.5nm. 230 M/mm2 translates to 33nm "half-pitch". Of course, transistors aren&#x27
7.
by seastarer 2y ago
Now I'm imagining submarines full of illicit maple syrup
8.
by seastarer 3y ago
You can implement a virtual machine monitor (e.g. KVM) and then launch a Linux virtual machine to run drivers you lack.
9.
by seastarer 4y ago
The energy cost of extracting oxygen is higher than you'd get from burning it.
10.
by seastarer 4y ago
ScyllaDB is a rearchitecting of Cassandra, not just a rewrite.
11.
by seastarer 4y ago
Some more data on Google PD: https://raw.githubusercontent.com/scylladb/diskplorer/master... Very odd - notice how the latency is high when the read IOPS are low. When the read IOPS climb, 95th percentile latency
12.
by seastarer 4y ago
No.
13.
by seastarer 4y ago
Persistent Disk read latency is usually good, but jitters up to 100ms. The scheduler can compensate for high latency (essentially applying Little's Law) but cannot compensate for jitter without saturating the disk.
14.
Russia to drop out of International Space Station in 2024(theguardian.com)
6 points by seastarer 4y ago|0 comments
15.
by seastarer 9y ago
Specialized logging applications, databases, userspace filesystems, and virtual machine monitors.
16.
by seastarer 9y ago
It happens sometimes. Very often? Not in my experience
17.
by seastarer 9y ago
Multi-Terabyte SSDs are very common. An i3.16xlarge instance on AWS, for example, has 15TB of SSD storage.
18.
by seastarer 9y ago
> If you know your read and write patterns very well you can effectively use this for nearly asynchronous IO without the pains of AIO and few to none extra threads. This may work for sequential reads, but not for random reads.
19.
by seastarer 9y ago
The diagrams are now correct (the read/write diagram was placed under the mmap section by mistake).
20.
by seastarer 9y ago
I see what happened, the read/write diagram got placed under mmap.
21.
by seastarer 9y ago
Right, the mmap read hit is incorrect, I'll fix it up.
22.
ScyllaDB 1.7 released with counter support(scylladb.com)
2 points by seastarer 9y ago|0 comments
23.
by seastarer 10y ago
You're going to be right on that guess. It will take some time though.
24.
Clustered ScyllaDB benchmark, 10X Cassandra(scylladb.com)
9 points by seastarer 11y ago|0 comments
25.
by seastarer 11y ago
We plan to reduce power usage on low load eventually.
26.
by seastarer 11y ago
It ought to. There may be a minor porting effort involved. Note you need very recent gcc.
27.
by seastarer 11y ago
Thanks. We "disable" C-states by polling -- the cpu never goes idle. This is partly because dpdk doesn't support interrupts, and partly because using interrupts is a major performance hit. We have plans to improve this, bu
28.
by seastarer 11y ago
Do you have a link to this cluster-on-die mode?
29.
by seastarer 11y ago
In posix mode, seastar uses the host's TCP stack (instead of the internal super-fast stack). This is useful for development. While we haven't ported it to osx, it should be fairly easy as the code is portable. Note you'll n