SSD and total bytes written question

[NecroFlex]

So i have a 120GB 850 EVO SSD, had it for a while now, but never used it that much, when i installed samsung magician today again cause i reinstalled windows, i saw this:

I don't remember writing 4TB of data on it in total, was barely used the first year

 

Any clues on what it could be? Page file perhaps or?

[Godlygamer23]

The OS writes its own data during usage, and any programs that are installed contribute to this value. It's not a high number to begin with. According to CrystalDiskInfo, I've written 38TB to my SSD in the past near five years that I've had it.

[NecroFlex]

3 minutes ago, Godlygamer23 said:

The OS writes its own data during usage, and any programs that are installed contribute to this value. It's not a high number to begin with. According to CrystalDiskInfo, I've written 38TB to my SSD in the past near five years that I've had it.

It's strange cause i bought a 1TB 850 EVO that was used for a server and had stuff constantly written on it, but it's on 5.4TB, thus i was confused considering the OS was installed on the 120GB SSD like a month or so ago, before that it was on my HDD cause i was too lazy to change it.

[mariushm]

Think of programs you have running most of the time.

 

For example, applications like Firefox every few minutes will save to disk the state (what tabs are open, the addresses, a snapshot of the pages, stuff like that) so that in case you have a power reset or crash, the tabs and everything would be saved.

So basically every few minutes, a few KB to a few MB would be written to the SSD. 

Some websites have ads that constantly refresh/reload or other dynamic stuff that's constantly downloaded, so browsers would write that stuff to disk (or potentially hold it in ram for a while)

Also whenever you open a website, the browser will update its database of addresses you access to update various counters or things it tracks about the urls you enter .. for example if you access several websites that have "LIN" in the name and then you access this forum a second time, the browser would consider LINustechtips more relevant so next time you type in the address bar LIN it would automatically highlight linustechtips

Stuff like this is also saved in some files on your drive and usually, every write is about 4 KB of data

 

For this reason, I moved the Firefox profiles to a mechanical hard drive and created junctions so that when firefox tries to read or write the files from the default folder (on the SSD) it's actually redirected transparently to the mechanical drive. Did the same for temporary folders (and changed the ENVironmnent variables as well)

 

See mklink : https://technet.microsoft.com/en-us/library/cc753194(v=ws.11).aspx

 

[NecroFlex]

2 minutes ago, mariushm said:

Think of programs you have running most of the time.

 

For example, applications like Firefox every few minutes will save to disk the state (what tabs are open, the addresses, a snapshot of the pages, stuff like that) so that in case you have a power reset or crash, the tabs and everything would be saved.

So basically every few minutes, a few KB to a few MB would be written to the SSD. 

Some websites have ads that constantly refresh/reload or other dynamic stuff that's constantly downloaded, so browsers would write that stuff to disk (or potentially hold it in ram for a while)

Also whenever you open a website, the browser will update its database of addresses you access to update various counters or things it tracks about the urls you enter .. for example if you access several websites that have "LIN" in the name and then you access this forum a second time, the browser would consider LINustechtips more relevant so next time you type in the address bar LIN it would automatically highlight linustechtips

Stuff like this is also saved in some files on your drive and usually, every write is about 4 KB of data

 

For this reason, I moved the Firefox profiles to a mechanical hard drive and created junctions so that when firefox tries to read or write the files from the default folder (on the SSD) it's actually redirected transparently to the mechanical drive. Did the same for temporary folders (and changed the ENVironmnent variables as well)

 

See mklink : https://technet.microsoft.com/en-us/library/cc753194(v=ws.11).aspx

 

Oh...well i mean i have Chrome always open with like...100 tabs or so

 

Found the culprit then i guess

[mariushm]

17 minutes ago, NecroFlex said:

Oh...well i mean i have Chrome always open with like...100 tabs or so

 

Found the culprit then i guess

You can try to nail it down further by using Resource Monitor or other tools that can log the amount of disk writes per application

 

Process Explorer from SysInternals Suite can show I/O writes (but not only to physical files, so not quite as useful) - you can right click on the columns and add I/O writes column to see the writes for all processes. It's an excellent tool for other purposes though, quite good replacement for task manager

 

Process Monitor from the same package can be much better.. for example just by adding two filters

 

IF process name IS NOT firefox.exe THEN EXCLUDE  - this hides all the events from all applications except firefox.exe

IF operation IS NOT WriteFile THEN EXCLUDE  - this hides events like opening file, closing file, opening tcp/ip connections etc i'm only interested in WriteFile which happens when data is written to a file (not necessarily physically written, data can still be cached by the OS and written later in bigger chunks)

then I  can see exactly what ONLY firefox.exe wrote to disk and where... as you can see in the picture below it updates cookies database and webappstore and sessionstore (the constant updates are mainly due to the background refresh the forum does to let you know if someone PM'd you or for notifications .. also when composing message what you write is periodically saved in database

You can also see that SQLite (the database engine) likes to write chunks of 32 KB to disk regardless if only a few bytes are changed or added or whatever.

 

 

( zSystemFolders is my redirect folder, used junction to link folders from the SSD to this folder transparently, apps think they're writing on the SSD while they do writes on a mechanical drive)