What would be a proper way to shutdown a sata disk connect with a usb interface ?

[borissh1983 at gmail.com]

On Sunday, 16 December 2018 10:13:17 IST shimi wrote:

> umount (assuming -l is not used), by definition, cleanly un-mounts the
> filesystem - it makes sure all pending writes are written and all metadata
> is cleanly committed, then completes. This makes 'sync' unnecessary - the
> filesystem would not be considered unmounted before all blocks were already
> reported written by the disk. So your 'sync', IMHO, does nothing. I assume
> it returns immediately (assuming no dirty data exists on other fs's...).
> You would see the umount waiting the way you would expect sync to wait (if
> you reversed the order...)
> 
> see also
> https://unix.stackexchange.com/questions/345917/does-umount-calls-sync-to-co
> mplete-any-pending-writes
> 

It must be a relic or a cargo cult action on my side, I was always calling 
sync AFTER unmounting drives. and wait little bit.

> sdpram -S 30  /dev/sdX (I'm not sure if does anything honestly)
> 
> > Wait for ~20 minutes
> > physically touch the disk if I feel any movement , if not unplug the power
> > the
> > usb cord and then unplug the power plug.
> 
> To what end?

The sata to usb interface from the laptop.
it should had say : 

1. unplug usb cable from the laptop
2. unplug power cable from the wall socket

> Why do you believe this is different from a normal shutdown of
> your computer with your internal HDDs where the filesystems get unmounted
> (the rootfs being re-mounted read-only) and then power off of the ATX power
> supply?
> 

I do not have the slightest idea how the sata to usb interface works, and if 
it behave the same as a direct sata to motherboard and atx power cut work. 

In a pc I would never unplug a sata cable while the power was still in, in 
fact I will never disconnect ANY cable inside a pc while the pc was still on. 

A sata to usb interface has it's own power source (I forgot to mention it). 

> I have both SSD and plain old HDDs plugged this way.
> 
> > I'm feeling that I'm working in an unsafe manner, does any of you have a
> > better suggestion how to shutdown the devices correctly to prolong the
> > disk
> > life ?
> 
> What is unsafe in your opinion? Can you please elaborate? How does it
> relate to prolonging disk life? Clean unmount is (so I believe...) for
> filesystem integrity more than anything else...
> 

"When in doubt, stop it's wrong" is a good line for any technical field, I do 
not know enough so I ask.
 
I had a disk die recently (it was only three and a half year old disk). which 
was no longer recognized or even show any indication of starting up. I even 
tried to plug the sata disk into a pc and the bios there did not recognize  
it. 

I have  replaced the sata to usb interface and the power block to a new one 
(just in case it was the interface who killed the drive).