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Best Drive To Prevent Unrecoverable Read Error (3/28/2014)

wpirobotbuilder

Entry posted by wpirobotbuilder

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Here are the product sheets for the enterprise/NAS drives I was able to find:

Western Digital

XE Series: < 10 in 1017

RE Series: < 10 in 1016

SE Series: < 10 in 1015

Red Series: < 1 in 1014

Seagate

Enterprise 10K: < 1 in 1016

Constellation ES: < 1 in 1015

Constellation ES.3: < 1 in 1015

Constellation CS: < 1 in 1014

NAS HDD: < 1 in 1014

HGST

Ultrastar 7K4000: < 1 in 1015

A lower BER means less of a chance of having a RAID require a rebuild due to an unrecoverable read error (URE).

I think it's really weird that WD specifies the BER for their datacenter drives in terms of < 10 in 10^15, 10^16, etc, rather than in terms of < 1 in 10^15, 10^16, etc. Very confusing.

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wpirobotbuilder

These numbers only make me laugh after reading all the threads on this forum with the drives recommended, under the limit.

I suspect many members running WD Reds in RAID 5/6 on a hardware controller will encounter a URE during a rebuild if they have a drive failure. Plus there's the whole issue with the controller being a SPoF.

 

A hardware RAID 5/6 with SE or Constellation drives would be ten times less likely to hit a URE during a rebuild. But since most people use drives with TLER it won't be a problem unless multiple drives hit a URE for the same piece of data (very unlikely).

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