analogkid

It's a small world. Denise used to sit outside my office until I moved moved to a new location. ;-)

She has forwarded requests that people may occasionally send directly to me in the past and I generally try to respond. I prefer all communication be done through proper channels to avoid any "issues" that might arise.

I have a son who is a CS major in college now. I completely understand how challenging (and borked) the hiring/interviewing process is now as I speak with him about the frustrations he experiences. Which is why I try to be approachable when people have queries.

I should add that Renaissance Technologies is hiring!

https://www.rentec.com/Careers.action

My group is looking for very strong Java/Kotlin developers.

The tone of many comments here is disappointing. I'm really surprised at the number of people suggesting illegal activity.

Why is it so hard to accept that someone did the math?

Sure. Our small ~500GB volume (on an OpenSuse system) became essentially read-only with ~50GB of free space on it. The error code was no free space. We clearly didn't have the "toolkit" needed to deal with such an issue. The box was a secured system, so we couldn't add an additional device easily (non-keyboard USB devices were disabled in the kernel, for example). Also, the read speed off the volume became terribly slow...it would've taken days to get the data off the device. We tried many commands to try to unbork the volume, with no luck. Even some of the btrfs commands were taking hours to run and became unkillable. We had to reboot the box several times...

We had a 24 hr old copy of the data and we were able to lift the few very important modified files off the device. So we reformatted with XFS and were able to restore the volume to a working state.

Fortunately, the failure happened late on a Friday so we had the weekend to put it all back together again.

I have only hatred for btrfs. Complete crap. Only our business competitors should use it ;-) We only chose to use it on this small system just so that we could get meaningful experience with it. We also had it running on another system where the next weekend we took emergency downtime and removed btrfs from it as well.

I've been using ZFS in production since it was released in Solaris 10 in 2006. It isn't perfect either. We did once hit a performance degradation which was fixed a few days later with a kernel patch. But that was 10 years ago. We never lost any data or sleep over it. We no longer have any Solaris boxes; they were all converted to Centos with ZFS. The main active ZFS pools are all 6TB of mirrored NVMe storage on systems with 2TB of ram and 48 core of INTC Platinum cpu's. Works like a charm.

No, OpenZFS is alive and thriving and we use it in production on many Centos systems.

btrfs is a awful. We used it for a brief time on a production system with vanilla mirrored drives. Absolutely horrible. I will never use btrfs for anything ever again. I've been running unix systems for 30 years; even the darkest days of UFS was not that bad.

Renaissance Technologies | Java and Kotlin full stack developers | NYC | Onsite, Full-time

https://www.rentec.com/ The worlds most successful hedge fund.

Looking for developers to contribute to back office functionality, for essentially everything after the trade is made. We generally run Linux/JVM/Postgresql stack with an ongoing switch to Kotlin. Been in business for 30 years. We are stable and profitable. Resumes to careers@rentec.com

Must have college degree with high GPA in math, physics, computer science or related fields. We typically desire many years of experience, but will consider recent graduates if the match is very strong.

Nice article, but doesn't actually demonstrate that connections setup and tear down is the bottleneck. If you really have 500 active connections all "shouting" at the database simultaneously, the fact that those connections were obtained from a pool or not isn't going to change the throughput of the database.

Pooling introduces numerous other issues as well. For example, clients probably shouldn't all be using the same entitlements to connect, right? Surely there are some segregation of duties and roles that clients will be using alternative entitlements into the system?

Finally, you have to show some before and after results. This article simply asserts that connection pooling would improve the situation, but does nothing to demonstrate the point. Even the details of the server matter...how many cpus, how many drives, HDD or flash, what file system is being used?