How to reduce an application RAM memory use on Mojave

I got (quickly) a reply from Backblaze, It is helpful!

It is a good explanation why bztransmit need lots of RAM, and I cannot really complain as I have lots of files to backup

This being said, I would love to find a way to select the amount of RAM I can decide to allow or not to a dedicated application

For everybody's info I put it here in full

Zack, Dec 30, 16:37 PST:

Hi there,

Our system is showing you are running MacOS Mojave, Vista is a Windows OS. Our system does operate correctly on that OS. 

The issue is the number of files you have selected for backup. Our program uses a master index file called bzfileids.dat to record and identify every file that is backed up. This file is read into RAM every time bztransmit runs, so it can verify what has been backed up and whether something can be deduplicated. 

On most systems, this index is under 100MB in size. It's about 58MB on my own main machine. Yours is over 3.8GB in size, partially because you have over 10 million files selected for backup. With this many files and a bzfileids.dat file of that size, bztransmit will always take up at least 4GB of RAM on your machine whenever it runs. 

Now, there are several things that contribute to this file being large:

A) If you have ever renamed a Time Machine folder at the top of your hard drive, Backblaze will bloat up trying to back it up. It is absolutely not supported to "back up a back up" and Backblaze can only function properly backing up the originals.

B) Lots of files. If you knew of a folder with hundreds of thousands of small files that didn't change much you could back them up differently or exclude them from Backblaze backups.

C) Renaming top level folders with a lot of files. For example, if your top level folder name is "/my_music" and it contains 100,000 file names in it, then when you rename it "/my_great_music" Backblaze needs to add all of those filenames to that bzfileids.dat file which bloats it up. So the best thing you can do is keep your enormous folders the same over a long period.

D) Shorter Path Names. It would be best if your hundreds of thousands of files are on a disk called "d" instead of "disk_that_contains_files" and the top level folder is called "f" instead of "folder_for_lots_of_files". Etc. The shorter the paths, the smaller the bzfileids.dat file is.

It's possible to shrink the bzfileids.dat in case they've been temporarily bloated by one of the above situations, however it requires reuploading all data to the Backblaze servers. You can follow these steps to do that: 

1. Visit https://secure.backblaze.com/user_signin.htm and sign in to your Backblaze account with your email address and password. 

2. Click on the "Account" link in the upper left hand corner 

3. Select your "old" computer from the list of computers. 

4. Click the "Delete Computer" link next to it. This will delete the backed up data, the bloated bzfileids.dat and free up the paid license. 

5. Click on "Overview" 

6. Click the download link for your operating system in the bottom right corner. 

7. Install Backblaze.

Here's the problem. If you cannot reduce the number of files or path names significantly, then you absolutely are going to encounter this issue again. If you uninstall and reinstall without changing anything, then your backup might start working again, but you will reencounter this problem a little ways down the road.

Regards, 

Zack - Meet me!

Backblaze Best Practices

The Backblaze Team

Thanks Kappy

I already use timemachine

I want and I need an offsite frequent and automatic backup

this is not answering my technical question

there must be a way to only allow a dedicated amount of ram to an app

this being said I will complain backblaze about their poorly designed software not adapted to Mojave

Cheers

Please don't end me 2009 tips for Mojave, they are outdated

"We could offer other solutions to poor performance."

> Please explain, as you looks like someone knocking at the door to sell me a 1995 vacuum cleaner

Thanks, I also make a CC using CarbonCopyCloner every week on an external drive.

Then I swap the drives I am using for CCC every week

The freshly made drive is zipped and I upload it as an attachment using Backblaze.

Backblaze isn't a full Carbon Copy of your computer, it is saving almost all datas, but not the system itself.

Cheers

Sorry, 

this is BobTheFisherman who is looking to me like the door to door vacuum salesperson

1 - He is speaking like someone who obviously never needed any additional ram. 

I want to reduce the amount of RAM taken by Backblaze to have all of my other application running smoothly. I don't mind Backblaze if it is slower.

2 - What are you tying to sell with your "We could offer other solutions to poor performance."  

I admit and I know Backblaze isn't the best one, but it is allowing me to store up to 10 terrabytes for $5 a month. Is there any better value for the money today?

I already have lots of outside backups, I wanted a cheap external one to outsource, as an additional level of security, what to you do if your home burns into flames or get flooded (not in the same time!)

You are right, but I like the automatic way to never forget anything,

backblaze support made a very detailed answer to my question,

for once, a support team is making an excellent work, realy adapted to my specific question, I can only be happy with their reply.