We're acquiring several 1U servers
with (8) 2.5" drive slots. Although we can use either SATA or SAS, there is a large
price variance as soon as you order 16 or 24 of these drives, so we are looking at the
2.5" SATA interfaced drives.
I know that Seagate
and WD both make "Enterprise" 2.5" drives, which are fast (10k and 15k RPM), but are
also fairly expensive.
What issues would we run
into using 7200RPM 2.5" non-Enterprise drives? By the way, these will be hooked up to a
RAID controller (though, they may just be configured as JBOD). These drives are almost
$100 lower in price, per drive.
In
addition to the problems above, you may have additional issue running these drives in
RAID configuration due to the lack of TLER. (If you are considering a model without.)
This quote references desktops and the RAID Edition drives but I imagine the same to be
true in the 2.5" line if you substitute in "notebook" and "enterprise" or "SAS" where
applicable.
Western Digital manufactures desktop edition hard drives and RAID Edition hard
drives. Each type of hard drive is designed to work specifically in either a desktop
computer environment or a demanding enterprise environment.
If you install and use a desktop edition hard drive connected to a
RAID controller, the drive may not work correctly unless jointly qualified by an
enterprise OEM. This is caused by the normal error recovery procedure that a desktop
edition hard drive uses.
When an error is
found on a desktop edition hard drive, the drive will enter into a deep recovery cycle
to attempt to repair the error, recover the data from the problematic area, and then
reallocate a dedicated area to replace the problematic area. This process can take up to
2 minutes depending on the severity of the issue. Most RAID controllers allow a very
short amount of time for a hard drive to recover from an error. If a hard drive takes
too long to complete this process, the drive will be dropped from the RAID array. Most
RAID controllers allow from 7 to 15 seconds for error recovery before dropping a hard
drive from an array. Western Digital does not recommend installing desktop edition hard
drives in an enterprise environment (on a RAID controller).
Western Digital RAID edition hard drives have a feature called TLER
(Time Limited Error Recovery) which stops the hard drive from entering into a deep
recovery cycle. The hard drive will only spend 7 seconds to attempt to recover. This
means that the hard drive will not be dropped from a RAID array. Though TLER is designed
for RAID environments, it is fully compatible and will not be detrimental when used in
non-RAID environments.
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