5

I’m sorry if this question is really stupid, but this is basically what I have been thinking about constantly. Suppose I run:

: cat ./somefile.txt

A few hundred times a second. How much faster is my hard drive going to die?

6
  • Why would you call cat a few hundred times a second to begin with? Are you trying to parse something?
    – JustXanny
    Jul 7, 2011 at 13:22
  • 4
    FWIW, running : cat somefile.txt does not run cat. The : built-in does nothing at all.
    – user1686
    Jul 7, 2011 at 13:50
  • : cat somefile.txt > otherfile.txt creates otherfile.
    – Blub
    Jul 7, 2011 at 13:58
  • 38
    It's usually a wasted effort -- they never come until they hear the can opener. Jul 7, 2011 at 17:46
  • @Blub, actually your command does very little : cat somefile.txt > otherfile.txt will not copy the contents of somefile.txt to otherfile.txt; otherfile.txt will be present after the command, but will be empty (even if it originally had contents). : `cat somefile.txt > otherfile.txt` will copy the contents of somefile.txt to otherfile.txt without displaying the output. See: gnu.org/software/bash/manual/html_node/… and stackoverflow.com/questions/3224878/…
    – dr jimbob
    Jul 7, 2011 at 18:28

3 Answers 3

20

Seven. But seriously, it's hard enough to know how long a disk will last while idling let alone under heavy load. There's no answer other than to say it will probably wear the disk faster.

The better argument against this is it would generally be quite slow. Why would you need to hammer the disk like that?

If you're looking to find out when something changes, perhaps look at inotify which is a kernel-based file event system that can call some code when something happens, negating the need to hammer the disk.

There are wrappers like pyinotify to make things easier.

1
  • 1
    +1 for the pointer to inotify. I hadn't heard of it before and it looks like a useful tool. Jul 8, 2011 at 14:16
19

It may have no effect at all, depending on the size of somefile.txt - if it's small enough for the kernel to cache it in RAM, the file will only be read once from disk and subsequent iterations will retrieve it from the cache.

Even if running that command repeatedly does have an effect on your drive's lifetime, it will be due to the file being read repeatedly. Whether you use cat or some other program to read it is completely irrelevant.

1
  • 1
    I guess nowadays there are very few files you would want to cat large enough not to be cached completely. So indeed, only the first time the disk is going to feel it.
    – Joey
    Jul 7, 2011 at 14:28
3

This reminds me of that study Google did about Harddrives. Since they go through a lot of harddrives, they did an informal study to see if there was any significant correlation between the lifetime of a HD and a list of factors that include temperature, power cycles, activity levels, etc. The only significant factor they found was age, I believe. The study is called "Failure Trends in..." something something.

I wouldn't worry too much about HD usage eating your drive.

1
  • Do you mean this study? Quote (emphasis mine): »One of our key findings has been the lack of a consistent pattern of higher failure rates for higher temperature drives or for those drives at higher utilization levels. Such correlations have been repeatedly highlighted by previous studies, but we are unable to confirm them by observing our population. Although our data do not allow us to conclude that there is no such correlation, it provides strong evidence«
    – Socowi
    Mar 18, 2021 at 10:09

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