[colug-432] HDD Questions-question about SSD wear

[Johnathon Scott]

Thanks, Rick for mentioning the Backblaze report, I had totally forgotten about that.

It probably doesn't matter at all in this use case but this discussion made me wonder whether file system choice has an effect on the life of SSDs.

Conventional filesystems like UFS, ext2 rewrite file objects in place.  As was mentioned, EEPROM/flash memory has a finite numnber of write/erase cycles per block.  So unless the disk is mounted with "noatime" option, each time a file object is accessed, metadata is written to the coresponding inode.

Am I correct in my understanding that log-structured file systems like F2FS, LogFS, and ZFS (I might be wrong on ZFS considering ZIL/L2ARC) don't do this?  Updates are not stored in the exact same physical location.  Since storage is treated as a circular log, changes are writen to the head of the log.  Along with providing a nice mechanism for snapshotting wouldn't these sort of FS provide a sort of "wear leveling" because by obeying FIFO every block gets used evenly?

Johnathon 



On Thu, Sep 08, 2016 at 08:36:57PM -0500, Rick Hornsby wrote:
> 
> 
> > On Sep 8, 2016, at 16:11, tom <thomas.w.cranston at gmail.com> wrote:
> > 
> > I'm running a 9 year old Dell Inspiron 1520 laptop. Think Toyota 
> > Corolla. Not fancy but get's the job done. Easy to service. I don't 
> > think a lightning fast drive is going to get me down the road much 
> > faster. Please correct me if I am wrong. I am concerned about 
> > reliability. The Seagate Barracuda 750 GB drive I have had for around 3 
> > years is showing beginning to fail
> 
> The first priority is to get anything you care about copied off that failing drive, as quickly as possible. Everything else is secondary. Get your stuff copied onto *any* known good drive, even if you have to make an interim purchase of a 3.5" or external drive you're not going to use in the laptop. There's no if with a failing drive, there's only borrowed time and luck. One or both will run out.
> 
> As for a new purchase, for the most part, any modern on-brand drive will have more or less the same reliability.  Once you start going to off-brand + lowest price, you increase the risk of unexpected and early failure. It's the old adage "you get what you pay for". 
> 
> 3 years for a 2.5" drive carted around in a 9 year old laptop isn't awful. The way Dell built those laptops they figured you'd have to buy a new one every 18-24 months.
> 
> Drives do not last forever. The tolerances of the moving, mechanical parts are very tight. The head can fall, which will pretty much destroy the platters, moving at 5400 or 7200 RPM as they are. The magnetic properties of the platters begin to break down over time, resulting in bad sectors, etc. While SSDs are more reliable if for no other reason than simply because they have no moving parts, they too have a finite life because they can only take so many write cycles.
> 
> The best thing you can do is have good, current backups of anything you care about. Especially on a laptop which could get dropped, stolen, or - being 9 years old - decide to fry itself ...and your little dog^H^H^Hdrive, too. That'll ruin your day if you don't have any backups.
> 
> 
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