Quick or Full format for Refurbished drives?

Hi Everyone,

What are your opinions on HDD formatting prior to plotting to a disk? I’ve been purchasing refurbished drives that show as being uninitialized in Windows when I first plug them in. So I’m wondering in this case if you think there’s any benefit to performing a full format?

Thanks in advance for any responses!

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My recommendation: Delete the full partition(s) that exists, recreate one full partition, then do a ‘Quick Format’. A full format, rather than quick means having the heads actually cover the entire surface of a drive, a task that can take many, many, many hours depending on drive size, and not really a worthwhile effort.


The quick format just kills the file structure without touching / deleting the old data and creates a new / clean file structure. What it means is that the OS will think that the drive is empty (it is from the file OS perspective), but if you take some disk recovery tools, you can potentially still recover the old stuff.

The full format will permanently erase old data, plus will also test the surface for bad sectors. I am not sure whether the full format will properly mark / relocate those bad sectors, though.

Permanently erasing the old data is rather a useless task as new plots will do the same job. However, if you are not testing your refurb drives, that testing for bad sectors will give you some info about the state of that drive (e.g., whether there are bad sectors there).

I would say that it is better to know about potential bad sectors before the plotting starts. In case the full format only informs about those, you can use some other utils to do that job. It is also worth to note that bad sectors under the plot may not be harmful. Sure, they will kill the whole plot if the indexing part will sit on such bad sector, but if data part sits on such cluster, that may not be a reason to be concerned (a tiny portion of data will be destroyed). Still, depending how those bad clusters are handled, they may slow down the lookup process (if that data part needs to be read). So, testing for those bad ones and either relocating them or marking as recovered ones is a good thing to do before plotting starts.

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Full format may not show you if the drive is starting to fail and I suggest zeroing whole drive and checking SMART counters. I always run SMART long test on any HDD I get right away to check if there are any apparent issues. SMART #5 counter will show you if there are any remapped bad sectors which may not be reported by the drive during format by the format utility and depending on how the HDD firmware deals with bad sectors but HDD firmware should increase this counter when it remaps a sector. There are of course other interesting SMART stats you may want to check (ex: power on hours) which will provide you more insight in to how the HDD was used as long as this is not professionally refurbished (aka white label) HDD which have all the SMART stats cleared. SMART tests are non destructive read tests so issues may still show up when formatting/writing so you may want to at least zero the drive (or long format) and then check SMART counters again with either smartctl (Linux) or GSmartControl (Windows).

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I do the exact same thing with my drives. I store the output from smartctl for further comparisons. Actually, I first run smartctl -a before zeroing out and running long test to see whether new things are showing up. For a stable drive there should be basically no changes. However, Seagate are not really conforming to that (my understanding is that #1 and #7 are to be ignored for Seagate, although maybe those need to be interpreted differently for Seagate).

Although, I am not sure what equivalent of running dd to zero out the drive would be on Win side.

Also, recently one of my old drives started to show pending sectors (#197), and it was rather a nightmare to run dd then smartctl, and again dd / sc and again, … I cannot say that I know what to do in such case, other than toss such drive to the garbage bin.

if I recall correctly #197 happens when HDD tries to write to a sector and could not verify written data, it may retry and if it continues to have issues it will mark it bad and add it to #5 then save data to remapped sector. #198 is I think when sector is read but data does not pass CRC meaning data is toast, but do not quote me on these as I just recall from memory and my memory does not come with CRC :smiley: Either way all 3 of these mean bad drive especially if they continue to grow. HDD with few bad sectors (#5) is still perfectly fine for Chia as long as #5 does not keep growing so you would have to keep a watch on it with occasional long SMART test. I love how some support techs from the manufacturer side try to tell you that these values are OK and you can clear them with a “tool”, but I would not trust that HDD for anything critical. It is true that some manufacturers have the ability to recover bad sectors but that is just a gimmick in my opinion and attempt to mask a problem as likely something caused that bad sector (perhaps spec of dust?) and the issue will very likely come back.

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That bad drive was a learning experience for me, nothing more. I was trying to understand how those #197 sectors are being handled. On one dd run some were recovered, on another the same appeared once more, plus new ones were present. Even though, I got the disk to have that #197 empty, on the next dd run new sectors were there.

My take about those sectors is that if there are just few (especially at the beginning), those most likely indicate problems with the magnetic coating (weak magnetic spots). So, the number should not grow, but rather stabilize (few sectors over that problematic area). On the other hand, if new sectors will show up later, that means that the surface was scratched. If that happens, two things are potentially happening: 1. some particles are created when the head hit the platter, 2: head made a groove, as such at the edges of that groove are ridges, and those ridges will be hit by the head sooner or later creating more particles. Potentially the cause for the first touchdown is a wear in the head arm bearing, so the disk is a toasted, but may not yet be aware about it. The latest drives have potential good G force protection, so they may be able to take some shocks (box / drive was hit or hard moved). Otherwise, those USB drives would be dead in a month or so.

quick quick quick…

its not like your putting your family pictures on thies drives

doing a full wipe wont get u any more extra space
therefor being absolutely pointless especially just putting replicatable plots on there