drive selection for disk arrays
David Christensen
dpchrist at holgerdanske.com
Sat Mar 28 03:03:14 UTC 2020
On 2020-03-27 17:45, Karl Denninger wrote:
>
> On 3/27/2020 19:39, David Christensen wrote:
>> On 2020-03-27 02:45, Polytropon wrote:
>>
>>> When a drive _reports_ bad sectors, at least in the past
>>> it was an indication that it already _has_ lots of them.
>>> The drive's firmware will remap bad sectors to spare
>>> sectors, so "no error" so far.
>>
>> If a drive detects an error, my guess is that it will report the error
>> to the OS; regardless of the outcome of a particular I/O operation
>> (data read, data written, data lost) or internal actions taken (block
>> marked bad, block remapped, etc.). It is then up to the OS to decide
>> what to do next. RAID and/or ZFS offer the means for shielding the
>> application from I/O and drive failures.
>>
> Yes, but...
>
> Those drives that can do "SMART" will report (if you have a patrol
> daemon for it running) if they do a "silent" sector reassignment.
> Otherwise the OS is none the wiser and neither is ZFS (or anything
> else.)
I guess I need to RTFM:
https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/serial-ata-ahci-spec-rev1-3-1.pdf
> Needless to say if reassignments increase you might want to
> think about swapping the drive *before* it blows up!
Agreed.
> I have the daemon running on all my machines. It works nicely and has
> warned me a few times over the years. With that said it doesn't ALWAYS
> catch a drive before it pukes.
Are you referring to periodic, smartd, or something else?
# pkg install smartmontools
Updating FreeBSD repository catalogue...
FreeBSD repository is up to date.
All repositories are up to date.
The following 1 package(s) will be affected (of 0 checked):
New packages to be INSTALLED:
smartmontools: 7.0_2
Number of packages to be installed: 1
The process will require 2 MiB more space.
495 KiB to be downloaded.
[1/1] Fetching smartmontools-7.0_2.txz: 100% 495 KiB 507.1kB/s 00:01
Checking integrity... done (0 conflicting)
[1/1] Installing smartmontools-7.0_2...
[1/1] Extracting smartmontools-7.0_2: 100%
=====
Message from smartmontools-7.0_2:
--
smartmontools has been installed
To check the status of drives, use the following:
/usr/local/sbin/smartctl -a /dev/ad0 for first ATA/SATA drive
/usr/local/sbin/smartctl -a /dev/da0 for first SCSI drive
/usr/local/sbin/smartctl -a /dev/ada0 for first SATA drive
To include drive health information in your daily status reports,
add a line like the following to /etc/periodic.conf:
daily_status_smart_devices="/dev/ad0 /dev/da0"
substituting the appropriate device names for your SMART-capable disks.
To enable drive monitoring, you can use /usr/local/sbin/smartd.
A sample configuration file has been installed as
/usr/local/etc/smartd.conf.sample
Copy this file to /usr/local/etc/smartd.conf and edit appropriately
To have smartd start at boot
echo 'smartd_enable="YES"' >> /etc/rc.conf
David
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