Symlink to reduce write to disk?

tinh_x7 · 1. Juli 2016

Hi,

I'm currently using SSD for my OMV, and most main software are installed on it.
However, I plan to install another software onto the SSD, but I want to reduce the read/write to a specific data folder.
Folder2ram can't be use in this scenario because this folder needs to save data frequently.
Symlink can link to different drive and partition.
If I symlink (soft or hard) the data folder to another drive such as my RAID drive/data drive, will that reduce the I/O to my SSD?

Folder x is the folder that I want to symlink.

Here's the scenario:

----Software ABC
--- folder A
---folder b
------Folder B
----folder x

Thanks.

ryecoaaron · 1. Juli 2016

How often is "frequently"? An SSD should be able to handle it if it is a good quality SSD.

tekkb · 1. Juli 2016

Give the precise paths.... not this scenario stuff.

/abc/a
/abc/b
/media/uuid/

What folders do you want to move to the data drives?

Yes, SSDs are getting better and better. SD cards are as well.

tinh_x7 · 1. Juli 2016

I"m using a Samsung EVO 850.
I haven't finish install the software yet.

Not only I'm concerning the write but it may run out of space in the future on the SSD.
That's why I want it to use it on the /media/

The software would be /opt/ABC/x ----> /media/UUID/www/ABC/x

Would the symlink help though?

tekkb · 1. Juli 2016

Yes, it would reduce writes on the SSD. I tell you how to do it regardless.

stop the service, whatever the command would be.
service abc stop

mv /opt/ABC/x /media/UUID/www/ABC
cd /opt/ABC/
ln -s /media/UUID/www/ABC/x x

ryecoaaron · 1. Juli 2016

Sure but you might have to mount the data drive without the NOEXEC flag. The software won't let you set where the log files are located in the config? This would be better than using a symlink.

tekkb · 1. Juli 2016

It depends on what you are moving and it's function. You should tell what application this is.

tinh_x7 · 1. Juli 2016

https://snipeitapp.com/

The main three folders that have a lot of read/write:

Code

chmod -R 755 app/storage
chmod -R 755 app/private_uploads
chmod -R 755 public/uploads

Meaning the drive would read the symlink from the SSD then write it to /media/ ?

tekkb · 1. Juli 2016

It would not read or write from the system drive. It is basically redirected to the data drive for the read/writes by the symlink.

I would have to install snipeit to check it out. No time right now. Are you sure it is read/write intensive???

tinh_x7 · 1. Juli 2016

This is what the documentation says:

Zitat

You’ll need to make sure that the app/storage directory and its subdirectories are writable by your web server, since caches and log files get written there. You should use the minimum permissions available for writing, based on how you’ve got your web server configured. You also need to change permissions for your uploads directory for user avatars and model images.

I"m going to move the three folders to the media drive, and then symlink them to the system drive.
Thanks guys.

ryecoaaron · 1. Juli 2016

Unless you have thousands of users using something like that, it isn't going to have anywhere near the number of writes that collectd/rrdcache has. I don't think it will use that much space either. I don't think you need the symlink. And remember that reads don't wear out an SSD.

tekkb · 1. Juli 2016

When they were working on the flashmemory plugin they used something to see what folders/files were getting a lot of writes. That was very helpful. Probably would be for you too.

Ancient_Wizard · 6. Juli 2016

Zitat von tinh_x7

I"m using a Samsung EVO 850.
I haven't finish install the software yet.

Not only I'm concerning the write but it may run out of space in the future on the SSD.
That's why I want it to use it on the /media/

The software would be /opt/ABC/x ----> /media/UUID/www/ABC/x

Would the symlink help though?

Alles anzeigen

I like this thread. I have same hardware and similar questions and concerns.

I have already installed Flashmemory and will install in again when I reload onto the smaller Samsung EVO 850 I recently bought.

I will read further about symlink and its uses and I will look for posts specifically related to SSD configurations.

I have also created a folder with links to posts I have found useful so I can more easily find them when I want to compare or review previous posts.

Jetzt mitmachen!