ZSTD Compression

[JJ Fullmer]

So I just updated to RC 15 and made a new image at zstd level 9. I was using gzip level 5 before. The image is still currently downloading, estimating the full time to be about 12 minutes. With gzip the download was taking around 3 minutes. This is a 6th gen i5 client and the fogserver is on a vm with 8 vcpus (intel xeon something something) and 16 GB ram. There is also a storage node on a older server with a little less power, but still imaged around 2-3 minutes.
The size of the image uncompressed is ~15 GB and it is 7.5 GB compressed with zstd. My old image was ~18 GB and with gzip level 5 it compressed to 6.7 GB.

So what did I do wrong? Is the difference between 9 and 11 really that substantial? Should I re-upload that image? Also split vs non split? I saw the post on the topic of it being better for multiple images, but are there any other considerations in regard to speed?

[Tom Elliott]

@JJ-Fullmer ZSTD “mid” range is 11, compared to PIGZ “mid” range being 5-6.

I set my images to 19 now and it’s pretty awesome.

[JJ Fullmer]

@Tom-Elliott But at 19 are you sacrificing speed substantially?

[Tom Elliott]

@JJ-Fullmer Not at all.

[JJ Fullmer]

@Tom-Elliott I will give it a try then

[JJ Fullmer]

@Tom-Elliott What about split vs not so split?

[Tom Elliott]

@JJ-Fullmer Either or, shouldn’t matter in terms of performance.

[Junkhacker]

@Tom-Elliott i’m going to disagree with tom on the speed sacrifice with -19 setting. deploy speed, you won’t sacrifice much, and maybe even gain, but on capture it’s going to take quite a while longer. for me, i use -11.

[JJ Fullmer]

@Junkhacker Well deploy is where speed is more important to me.
I gave 19 a go with the split and it actually had some weird error on the first deploy, I was in a meeting in my office so I didn’t really get to see the whole thing, but then it auto-retried the task and worked proper the second time. 2 minutes 18 seconds. The image size on the server seems to still be bigger than pigz was with 7.1 GB for a 15 GB image instead of 6.7 G for the old 18 GB image. But, don’t need to be too picky about it.

@Tom-Elliott Two minor issues I noticed. The first time (the slow deploy) I queued the image after doing a full host inventory via the pxe boot on the host. I had not specified any snapins and it randomly added like 10 of them. The second time I queued it from the gui and deleted the snapins and the problem didn’t repeat itself. However in both instances the drive didn’t resize itself.

[Tom Elliott]

@JJ-Fullmer What version of fog are you running?

[Tom Elliott]

@jj-fullmer and I had a remote session and the cause of the resize issue as described was found.

The issue he was seeing was the resize allowed a partition to be sized larger than the boundary of the disk. This only occurred, as far as I could tell, in the case of 4k disks again, but I’ve added code to correct for this in ANY case of the chunk size passed in.

Just thought I’d give an update to the “resize” issue as it was described and I’ve released RC-16 in an attempt to ensure this is corrected for.

[JJ Fullmer]

Figured I should add, my speed issue was related to running PHPIPAM (a ip management tool) on my storage node server. It was slowing my image deploys down, not the zstd. It’s crazy fast at compression level 19 now.

[JJ Fullmer]

@JJ-Fullmer Well it wasn’t actually phpipam that was slowing it down.
I had some ssl logs running for a website running on that server. It was tracking access logs for every access of the ssl cert and site. Which was also adding up to over 400 GB of logs. I changed the apache configuration of the site to log much less. That solved the problem. So again, nothing wrong with zstd. Just wanted to have the right answer in case someone else happens to see a constant 5-8 Mbps transmit and receive on a storage node.