[CentOS] LSI MegaRAID experience...
m.roth at 5-cent.us
m.roth at 5-cent.us
Fri Jul 19 13:55:48 UTC 2013
John Doe wrote:
> From: Drew Weaver <drew.weaver at thenap.com>
>
>> If these drives do not have TLER do not use them with LSI controllers.
>
> Not sure about TLER on those Plextors...
<snip>
TLER would only show up on something that looks at a *very* low level on
the physical drive. What I know is that you can see it with smartctl -
from the man page: scterc[,READTIME,WRITETIME] - [ATA only] prints
values and
descriptions of the SCT Error Recovery Control settings.
These
are equivalent to TLER (as used by Western Digital), CCTL
(as
used by Samsung and Hitachi) and ERC (as used by Seagate).
READ-
TIME and WRITETIME arguments (deciseconds) set the
specified
values. Values of 0 disable the feature, other values less
than
65 are probably not supported. For RAID configurations,
this is
typically set to 70,70 deciseconds.
Note that knowing this was the result of a *lot* of research a couple-or
so years ago. One *good* thing *seems* to be WD's new Red line, which is
targeted toward NAS, they say... because they've put TLER back to
something appropriate, like 7 sec or so, where it was 2 *minutes* for
their "desktop" drives, and they disallowed changing it in firmware around
'09, and the other OEMs followed suit. What makes Red good, if they work,
is that they're only about one-third more than the low-cost drives, where
the "server-grade" drives are 2-3 *times* the cost (look at the price of
Seagate Constellations, for example).
mark
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