Re: Mixing WD red with older seagates

["Timothy D. Lenz" <tlenz@vorgon.com>]

On 9/9/2013 7:56 AM, Mathias Burén wrote:
> On 9 September 2013 15:38, Jonathan Wilson <piercing_male@hotmail.com> wrote:
>> On Mon, 2013-09-09 at 13:50 +1000, Tudor Holton wrote:
>>> Completely anecdotal evidence, but I was mixing WD Reds and Seagates in
>>> a QNAP RAID 6 each 3TB for a total of 6TB, and the Seagates kept making
>>> sounds like they were about to hurl.  Testing each drive individually
>>> with badblocks and smart came up with all drives OK.  But it kept
>>> chucking the WDs one by one.  Eventually I removed the Seagates and
>>> replaced them with WDs and since then no drives have been thrown out.
>>>
>>> I can only theorise that there may be a timing issue between WD Reds and
>>> Seagate.
>>
>> I wonder if the vibrations of the Seagates was causing the reds to be
>> thrown?
>>
>>  From what I've read (assuming I understand correctly) they are a low-ish
>> vibration drive with some fancy head positioning for alignment... but
>> should be limited to 5 at most, or at least are intended for upto 5
>> drive systems, so I wonder if this means that more than 5 could suffer
>> from vibrations throwing disks out?
>>
>> All that said, I wonder just how sensitive drives are nowadays? While I
>> have heard of tales of old where someone sneezing in the computer room
>> would cause large raid clusters to pop I don't know how true they are or
>> how sensitive drives are to the accumulative vibrations of many disks or
>> if its more of a case that as the number of disks increases then the
>> statistical chance of a drive failing increases to the point that it is
>> more likely to happen in coincidence with an external event, such as a
>> sneeze.
>>
>>
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>
>
> The sneeze story isn't true. Modern enterprise are sensitive, for
> example some 24k RPM fans will cause drives to fail within time, but
> 12k fans won't (40mm).
>
> However, if your room and your servers are normal, you've nothing to
> worry about.
>
> Mathias
> --

Sounds like what you guys are saying is that if I switch to the red, I 
need to replace all the seagate drives?

And it kind of sounds like they are overly touchy. I would expect them 
to be more immune to vibrations.

What I have is a 7' rack cabinet with a 2500w rack mount ups near the 
bottom. Above that a bit of space followed by a KBM switch and network 
switch. Then an HP laser printer on rails to pull it out for easier use. 
Above that a 4u case with my main computer which has 4 wd drives, ( 2 
160Gb and a 500Gb). Right above that is the linux vdr computer with the 
raid seagate drives.

And after mdadm fails a drive, it is bad. SMART and other programs 
report it so. mdadm hasn't failed this one yet, but it is just a matter 
of time. I get daily messages about the bad sectors.
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