Wol, et al --
...and then Wols Lists said...
%
% On 09/07/21 13:27, David T-G wrote:
% > Hi, all --
% >
% > I have a 1T drive
% >
% > jpo:~ # parted /dev/sdb print
% > Model: ATA ST31000524AS (scsi)
...
% > jpo:~ # smartctl -i /dev/sdb
...
% > Model Family: Seagate Barracuda 7200.12
%
% Barracuda ... DO NOT USE THIS IN A PARITY RAID ARRAY !!!
I am aware of the general problem, and I run the handy timeout script
# set the timeouts on the local drives
printf "${CBLU}Drive timeouts${CBLK}: "
for DISK in sda sdb sdc sdd sde sdf sdg sdh # a-d on mobo ; e-h on card
do
printf "$DISK "
smartctl -q errorsonly -l scterc,70,70 /dev/$DISK
if [ 4 -eq $? ]
then
echo 180 > /sys/block/$DISK/device/timeout
printf "${CYLO}180"
else
printf "${CGRN}Y"
fi
printf "${CBLK} ; "
done
echo ''
to reset as needed, and I even have no plans to parity this drive, but I
didn't realize that it was a problem disk! Thanks for the heads-up.
%
% Mirroring as you plan here is okay.
That's good. Of course, that then makes me scratch my head a bit since
it's still paired with other and needs to not blow up ... I'll have to
back and read more to see why mirror is safe.
%
...
% > and also two 500G drives
% >
% > jpo:~ # parted /dev/sdc print
% > Model: ATA WDC WD5000AAVS-0 (scsi)
...
% > jpo:~ # smartctl -i /dev/sdc
...
% > Model Family: Western Digital Caviar Green
...
% > that I plan to stripe together to use to protect the first. The Caviars
% > are listed as variable speed, but in practice they apparently are just
% > 5400 rpm, so I'd like to take advantage of striping to make them as fast
% > as possible.
%
% Caviar Green ??? Caviars should be okay, but the "green" moniker makes
Yeah, I'm not too happy about that ... Supposedly they will vary speed
based on demand, so they can deliver 7200rpm performance, but apparently
they always stay at 5400rpm and so they're just basic drives. Meh.
% me nervous. Check SCT/ERC, but striping/mirroring will be fine.
More of that confusion stuff :-) but happy.
%
% > This isn't the black magic ;-) of RAID10-on-two-drives,
% > so I don't have to think of one as "front" and one as "back", but do I
% > want more than one partition on each to stripe 4 or 6 slices to avoid
% > hammering on one, or do I just go with each device as a whole and let
% > mdadm handle the magic for me?
% >
...
% Okay, the simple approach.
%
% Create a single-device mirror using the 1TB and the special device
% "missing". Copy everything across and make sure it's all okay. (I'm
% assuming you can safely wipe this drive as it has nothing on it you wish
% to keep.)
Correct.
%
% Create a striped device using the two 500GB drives.
That's the fun part ... I'm thinkin' I'm just going to have to do sector
math to predict how large the new dev can be so that I can back into a
proper partition size on the 1T so that both halves can match.
How much overhead does md need for striping (RAID0)? Given these two
jpo:~ # parted /dev/sdc unit s print free
Model: ATA WDC WD5000AAVS-0 (scsi)
Disk /dev/sdc: 976773168s
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
34s 2047s 2014s Free Space
1 2048s 696250367s 696248320s ata-WDC_WD5000AAVS-00ZTB0_WD-WMASU06 raid
2 696250368s 967006207s 270755840s raid
4 967006208s 976773119s 9766912s reiserfs wwn-0x50014ee055b724ad
976773120s 976773134s 15s Free Space
500G disks (976773100 total sectors each, right?), how large a partition
can I create on this
jpo:~ # parted /dev/sdb unit s print free
Model: ATA ST31000524AS (scsi)
Disk /dev/sdb: 1953525168s
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
63s 2047s 1985s Free Space
1 2048s 1953521663s 1953519616s primary ntfs type=07
1953521664s 1953525167s 3504s Free Space
1T disk (1953525104 sectors, which is 21096 less than the 2ea others
together) can I create and expect to be able to match it across the pair?
Is this something I could mock up with overlays without destroying the
existing data?
%
% Add the striped device to the 1TB mirror.
At that point it becomes easy :-)
%
% Plan to replace all the disks with something like Seagate Ironwolves or
% Toshiba N300s in the near future :-)
Actually, I have four Seagate 4T drives
diskfarm:~ # parted /dev/sdd print
Model: ATA ST4000DM000-1F21 (scsi)
Disk /dev/sdd: 4001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 4001GB 4001GB xfs ata-ST4000DM000-1F2168_W300EYNA raid
2 4001GB 4001GB 134MB reiserfs wwn-0x5000c50069a8d76f
diskfarm:~ # smartctl -i /dev/sdd
smartctl 7.0 2019-05-21 r4917 [x86_64-linux-5.3.18-lp152.63-default] (SUSE RPM)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family: Seagate Desktop HDD.15
Device Model: ST4000DM000-1F2168
Serial Number: W300EYNA
LU WWN Device Id: 5 000c50 069a8d76f
Firmware Version: CC52
User Capacity: 4,000,787,030,016 bytes [4.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 5900 rpm
Form Factor: 3.5 inches
Device is: In smartctl database [for details use: -P show]
ATA Version is: ATA8-ACS T13/1699-D revision 4
SATA Version is: SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Sat Jul 10 21:38:12 2021 UTC
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
in another machine that I plan to upgrade to larger disks and hand down
to this one. They're older, and they don't
diskfarm:~ # smartctl -l scterc /dev/sdd
smartctl 7.0 2019-05-21 r4917 [x86_64-linux-5.3.18-lp152.63-default] (SUSE RPM)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org
SCT Error Recovery Control command not supported
have SMART error handling, but at least they aren't SMR :-)
%
% https://raid.wiki.kernel.org/index.php/Linux_Raid
%
% Read especially the page on timeout mismatch as this DOES apply to your
% Barracuda !!!
I'll go back again :-)
%
% Cheers,
% Wol
Have a great weekend!
:-D
--
David T-G
See http://justpickone.org/davidtg/email/
See http://justpickone.org/davidtg/tofu.txt
