[AAVSO-DIS] Data Services May Run Slow Tonight...

[Richard "Doc" Kinne]

Folks:

Last Wednesday morning the data server at the AAVSO (Occam) which runs the database and acts as a large file server developed a hardware fault. Wednesday morning was spent transferring this computer's functionality over to another one (Harmonia). This was a (semi) painless process and needed database functionality for all of our database services (VSP, Quicklook, VSX, etc.) and Citizen Sky was up and running again in a few hours.

However, the data - over 1.5TB of it - needed to be transferred from Occam to Harmonia. This has proved a challenge. Writing to the RAID disk on Harmonia is a CPU-intensive process. I have worked most of the day to try to get it LESS CPU-intensive, but the issue is that what needs to be copied are hundreds of thousands of 2MB FITS files (I asked Arne to stop taking so many pictures. He smiled and said, "The folder's ONLY 1TB? It's going to get MUCH bigger!"  :-)  ) and this makes the throughput slow due to disk indexing and journalling on a RAID system.

I have changed the priorities of several programs on the database server now. mySQL, our database engine now has the highest priority I dare give it. I am running the file copy on a lower priority than normal. Even given that, however, based on my experience this afternoon, I want to set an expectation that data services and Citizen Sky may be slow tonight.

Then we should be done.

Thanks, folks!
---
Richard 'Doc' Kinne, [KQR]
American Association of Variable Star Observers
<rkinne @ aavso.org>