memory

Rescue photos and other files from an SD or microSD card with PhotoRec

As a photographer who's taken and processed at least 200,000 photos in the past couple decades, you'd think I have a solid workflow that results in zero lost files... but you'd be wrong. 99% of the time, I follow the workflow:

  1. Import photos from memory card.
  2. Make sure backup of imported photos completes (so I have two local copies—I also have one copy back up to a cloud storage provider, so two local and one cloud backup).
  3. Format the memory card.

A lot of photographers shoot with two memory cards, and have photos written to both—that way the 2nd card would be a double-failsafe. But for most jobs, I don't do that. And one of my digital cameras doesn't even have two memory card slots, so this isn't an option!

Anyways, more often than I'd like to admit, I do something dumb, like:

Diagnosing Disk I/O issues: swapping, high IO wait, congestion

One one small LEMP VPS I manage, I noticed munin graphs that showed anywhere between 5-50 MB/second of disk IO. Since the VM has an SSD instead of traditional spinning hard drive, performance wasn't too bad, but all that disk I/O definitely slowed things down.

I wanted to figure out what was the source of all the disk I/O, so I used the following techniques to narrow down the culprit (spoilers: it was MySQL, which was using some swap space because it was tuned to use a little too much memory).

iotop

First up was iotop, a handy top-like utility for monitoring disk IO in real-time. Install it via yum or apt, then run it with the command sudo iotop -ao to see an aggregated summary of disk IO over the course of the utility's run. I let it sit for a few minutes, then checked back in to find:

2013 VPS Benchmarks - Linode, Digital Ocean, Hot Drupal

Every year or two, I like to get a good overview of different hosting providers' VPS performance, and from time to time, I move certain websites and services to a new host based on my results.

In the past, I've stuck with Linode for many services (their end-to-end UX, and raw server performance is great!) that weren't intense on disk operations, and Hot Drupal for some sites that required high-performance IO (since Hot Drupal's VPSes use SSDs and are very fast). This year, though, after Digital Ocean jumped into the VPS hosting scene, I decided to give them a look.

Before going further, I thought I'd give a few quick benchmarks from each of the providers; these are all on middle-range plans (1 or 2GB RAM), and with the exception of Linode, the disks are all SSD, so should be super fast:

Disk Performance

Disk Performance Chart

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