A friend of mine has given me a couple of 3.5" HDDs that he used with his PC and are only 3 or 4 years old that I would like to put in enclosures and use as backup devices. Would checking them with Disk Utility be sufficient prior to using them? I realise that I will need to put them in an enclosure to enable me to test them. Thanks.
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Testing external HDD's
- Thread starter Pete_202
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Disk Utility will not check every block.
Is it necessary to check every block? If a write error occurs, won't it just mark that block as bad and write to another block somewhere else?
https://superuser.com/questions/394...d-sector-on-an-external-usb-hard-disk-on-os-x
https://superuser.com/questions/148227/fix-bad-blocks-on-mac-hard-disk
https://superuser.com/questions/148227/fix-bad-blocks-on-mac-hard-disk/576380#576380
https://wiert.me/2020/03/13/macos-checking-a-disk-for-bad-blocks/
If you put the HDDs in a Thunderbolt enclosure, not RAID, then you get direct access to the SATA drive via the enclosure's AHCI controller. That might be better than using USB or FireWire for testing/recovery purposes.
Is it necessary to check every block? If a write error occurs, won't it just mark that block as bad and write to another block somewhere else?
https://superuser.com/questions/394...d-sector-on-an-external-usb-hard-disk-on-os-x
https://superuser.com/questions/148227/fix-bad-blocks-on-mac-hard-disk
https://superuser.com/questions/148227/fix-bad-blocks-on-mac-hard-disk/576380#576380
https://wiert.me/2020/03/13/macos-checking-a-disk-for-bad-blocks/
If you put the HDDs in a Thunderbolt enclosure, not RAID, then you get direct access to the SATA drive via the enclosure's AHCI controller. That might be better than using USB or FireWire for testing/recovery purposes.
Personally I'd:
- Buy an external USB 3 enclosure with a chip that supports SATA pass through. Most recent JMicron and ASMedia chips do this, but check.
- Download smartmontools for MacOS from here: https://www.smartmontools.org/wiki/Download#InstalltheOSXDarwinpackage
- Connect the drive in its enclosure.
- Open MacOS terminal and run an extended test. Instructions here: https://blog.shadypixel.com/monitoring-hard-drive-health-on-linux-with-smartmontools/
...this will test the electrical connections, the chipset, the motor and spindle of the drives; the extended text will also do a full scan of the physical disk surfaces.
- Buy an external USB 3 enclosure with a chip that supports SATA pass through. Most recent JMicron and ASMedia chips do this, but check.
- Download smartmontools for MacOS from here: https://www.smartmontools.org/wiki/Download#InstalltheOSXDarwinpackage
- Connect the drive in its enclosure.
- Open MacOS terminal and run an extended test. Instructions here: https://blog.shadypixel.com/monitoring-hard-drive-health-on-linux-with-smartmontools/
...this will test the electrical connections, the chipset, the motor and spindle of the drives; the extended text will also do a full scan of the physical disk surfaces.
I see nothing complicated about this.
First, get the drive connected to the Mac (external enclosure or perhaps with a USB3/SATA adapter/dongle).
Then, erase it with Disk Utlity.
I STRONGLY SUGGEST that you choose HFS+ (Mac OS extended with journaling enabled, GUID partition format) for platter-based hard drives.
(With HFS+, a platter-based drive is still "accessible" and "maintain-able" using many drive utilities. Not so with APFS...)
Then, run DU's "first aid" on the drive.
Do you get a "good report"?
If so, run first aid on it FIVE TIMES in succession.
Do you get a good report each and every time?
If I did, I'd then trust the drives for storage...
First, get the drive connected to the Mac (external enclosure or perhaps with a USB3/SATA adapter/dongle).
Then, erase it with Disk Utlity.
I STRONGLY SUGGEST that you choose HFS+ (Mac OS extended with journaling enabled, GUID partition format) for platter-based hard drives.
(With HFS+, a platter-based drive is still "accessible" and "maintain-able" using many drive utilities. Not so with APFS...)
Then, run DU's "first aid" on the drive.
Do you get a "good report"?
If so, run first aid on it FIVE TIMES in succession.
Do you get a good report each and every time?
If I did, I'd then trust the drives for storage...
Disk Utility's 'First Aid' is just a check on the file system structure & indexes; it doesnt check a drive for physical, electrical or media errors.
You can actually format a dying (eg bad sectors) HDD in Disk Utility, then run DU 'first aid' on it and it will pass provided that none of the core file system indices / trees happened to be stored on one of the failing parts of the disk. I've done this.
SMART is a more reliable check as it will scan the whole drive, regardless of any file system, and flag any physical errors it finds.
You can actually format a dying (eg bad sectors) HDD in Disk Utility, then run DU 'first aid' on it and it will pass provided that none of the core file system indices / trees happened to be stored on one of the failing parts of the disk. I've done this.
SMART is a more reliable check as it will scan the whole drive, regardless of any file system, and flag any physical errors it finds.
Just wanted to report back. I put the drives into their enclosures and used the trial version of DriveDx to check them. Both drives formatted fine and 'looked OK' using Disk Utility but DriveDx revealed that while one drive was OK the other one had had a long time in service and was nearly worn out. I will use it for now as part of a redundant backup but replace it in the near future.