Is write caching good for HDDs' life?

Question

I have a removable HDD for which Windows disabled write-caching by default, but on occasions I write a lot of data to that HDD and I was wondering, would enabling the caching temporarily improve the HDD's longevity?

Answer 1

Theoretically yes. Enabling write caching will reduce the total amount of write operations over time. However this concern is more relevant to SSD drives than to HDDs. SSDs have fairly small limited amount of write cycles.

Modern HDDs rearly faild due to heavy usage. Most common failure reasons are vibrations, external damage or low quality of the device itself. Reducing the amount of write operations is unlikely to increase the lifespan of the HDD.

I assume that you are aware of the disadvantages of the write-caching:

• It consumes your volatile memory (RAM)
• The file systems is more likely to be corrupted in case the computer shuts down improperly or external device is disconnected unexpectedly

All things considered I would not recommend to use write caching if your only concern is HDD's longevity

FYI, read these discussions

• Source 1
• Source 2

Answer 2

Not by any significant amount.

You are writing data to an external drive. Chances are that all that data will need to be written so you are not reducing the total volume of data to write to the drive. No win there.

You might reduce the amount of time that the head is seeking across the surface of the drive as caching may allow the order to be optimised slightly, but that is going to be a tiny proportion of the drives lifespan compared to actual data write time. No real benefit there.

Then there the fact that external drives can be unplugged by man or cat or petulant child at any second. If there was anything in the cache then that data is now lost. If you were using NTFS on the drive then what was there before is probably safe, but newly written data is at risk. With fat32 all bets are off, you could easily have trashed the entire filesystem by removing it at the wrong second.

Though the drive might feel slightly snappier, there is a reason why they disable write caching for removable drives, because write caching improves performance at the cost of data safety in the event of sudden removal or power loss.

Internal drives are fine due to NTFS being written to protect itself, all modern filesystem's are journalled and can at least recover to a "last good" state quickly. And an external drive with a modern fs could well be fine, but regularly trusting those mechanisms to save you is not a good way to work.

One day you'll forget to "safely eject" first so that the OS can flush the cache to disk, then you'll unplug it and put it on another machine and utter the first words of the recently bereaved: "Where did all my files go?"