Greg Zartman via smartos-discuss wrote:
On Sun, Jan 18, 2015 at 10:43 AM, Ian Collins <[email protected]
<mailto:[email protected]>> wrote:
Greg Zartman via smartos-discuss wrote:
I believe mirroring is the best practice so that if one SSD
dies, you don't lose any data before the slog has time to
write to the zpool.
You won't loose any data if a log device dies or is pulled. Logs
are only read from to recover data, such as after a power failure
which is why you should devices with power fail protection.
I wanted to follow up on this comment, as I just proved to myself that
you do lose your zones zpool if the log device fails.
I've been testing with Intel 3700 SSDs and a couple SmartOS boxes I
have. On one of the boxes, I lost the log device and the zones zpool
disappears on a reboot. I reproduced it 2 times by just pulling the
log device.
That's a) odd and b) shouldn't happen.
I just tried this on my test box, before:
# zpool status
pool: zones
state: ONLINE
scan: resilvered 5.07M in 0h0m with 0 errors on Tue Oct 14 20:52:54 2014
config:
NAME STATE READ WRITE CKSUM
zones ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c0t5000C50061621389d0 ONLINE 0 0 0
c0t5000C500616A8F4Cd0 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
c0t5000C500616B1514d0 ONLINE 0 0 0
c0t5000C500616B6247d0 ONLINE 0 0 0
mirror-3 ONLINE 0 0 0
c0t5000C500616A5799d0 ONLINE 0 0 0
c0t5000C500616AB0FDd0 ONLINE 0 0 0
mirror-4 ONLINE 0 0 0
c0t5000C500616B1721d0 ONLINE 0 0 0
c0t5000C500616B8891d0 ONLINE 0 0 0
logs
c2t0d0 ONLINE 0 0 0
c2t1d0 ONLINE 0 0 0
After ripping out the logs:
# zpool status
pool: zones
state: DEGRADED
status: One or more devices has been removed by the administrator.
Sufficient replicas exist for the pool to continue functioning in a
degraded state.
action: Online the device using 'zpool online' or replace the device with
'zpool replace'.
scan: resilvered 5.07M in 0h0m with 0 errors on Tue Oct 14 20:52:54 2014
config:
NAME STATE READ WRITE CKSUM
zones DEGRADED 0 0 0
mirror-0 ONLINE 0 0 0
c0t5000C50061621389d0 ONLINE 0 0 0
c0t5000C500616A8F4Cd0 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
c0t5000C500616B1514d0 ONLINE 0 0 0
c0t5000C500616B6247d0 ONLINE 0 0 0
mirror-3 ONLINE 0 0 0
c0t5000C500616A5799d0 ONLINE 0 0 0
c0t5000C500616AB0FDd0 ONLINE 0 0 0
mirror-4 ONLINE 0 0 0
c0t5000C500616B1721d0 ONLINE 0 0 0
c0t5000C500616B8891d0 ONLINE 0 0 0
logs
c2t0d0 REMOVED 0 0 0
c2t1d0 REMOVED 0 0 0
In messages:
2015-01-27T04:16:23.933059+00:00 smartos sata: [ID 801593 kern.warning]
WARNING: /pci@0,0/pci1458,b005@1f,2:#012 SATA device detached at port 1
2015-01-27T04:16:23.935137+00:00 smartos genunix: [ID 408114 kern.info]
/pci@0,0/pci1458,b005@1f,2/disk@1,0 (sd2) offline
2015-01-27T04:16:23.935152+00:00 smartos sata: [ID 801593 kern.warning]
WARNING: /pci@0,0/pci1458,b005@1f,2:#012 SATA device detached at port 1
2015-01-27T04:16:26.393644+00:00 smartos sata: [ID 801845 kern.info]
/pci@0,0/pci1458,b005@1f,2:#012 SATA port 0 error
2015-01-27T04:16:26.393703+00:00 smartos sata: [ID 801845 kern.info]
/pci@0,0/pci1458,b005@1f,2:#012 SATA port 0 error
2015-01-27T04:16:26.393746+00:00 smartos sata: [ID 801845 kern.info]
/pci@0,0/pci1458,b005@1f,2:#012 SATA port 0 error
2015-01-27T04:16:26.393754+00:00 smartos sata: [ID 801845 kern.info]
/pci@0,0/pci1458,b005@1f,2:#012 SATA port 0 error
2015-01-27T04:16:26.705046+00:00 smartos sata: [ID 801593 kern.warning]
WARNING: /pci@0,0/pci1458,b005@1f,2:#012 SATA device detached at port 0
2015-01-27T04:16:26.706899+00:00 smartos scsi: [ID 107833 kern.warning]
WARNING: /pci@0,0/pci1458,b005@1f,2/disk@0,0 (sd1):#012#011Command
failed to complete...Device is gone#012
2015-01-27T04:16:26.706920+00:00 smartos scsi: [ID 107833 kern.warning]
WARNING: /pci@0,0/pci1458,b005@1f,2/disk@0,0 (sd1):#012#011SYNCHRONIZE
CACHE command failed (5)#012
2015-01-27T04:16:26.707069+00:00 smartos genunix: [ID 408114 kern.info]
/pci@0,0/pci1458,b005@1f,2/disk@0,0 (sd1) offline
2015-01-27T04:16:26.707137+00:00 smartos sata: [ID 801593 kern.warning]
WARNING: /pci@0,0/pci1458,b005@1f,2:#012 SATA device detached at port 0
Plug them back in:
# zpool status
pool: zones
state: ONLINE
scan: resilvered 5.07M in 0h0m with 0 errors on Tue Oct 14 20:52:54 2014
config:
NAME STATE READ WRITE CKSUM
zones ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c0t5000C50061621389d0 ONLINE 0 0 0
c0t5000C500616A8F4Cd0 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
c0t5000C500616B1514d0 ONLINE 0 0 0
c0t5000C500616B6247d0 ONLINE 0 0 0
mirror-3 ONLINE 0 0 0
c0t5000C500616A5799d0 ONLINE 0 0 0
c0t5000C500616AB0FDd0 ONLINE 0 0 0
mirror-4 ONLINE 0 0 0
c0t5000C500616B1721d0 ONLINE 0 0 0
c0t5000C500616B8891d0 ONLINE 0 0 0
logs
c2t0d0 ONLINE 0 0 0
c2t1d0 ONLINE 0 0 0
2015-01-27T04:20:09.365522+00:00 smartos sata: [ID 801593 kern.warning]
WARNING: /pci@0,0/pci1458,b005@1f,2:#012 SATA device detected at port 0
2015-01-27T04:20:09.365553+00:00 smartos sata: [ID 663010 kern.info]
/pci@0,0/pci1458,b005@1f,2 :
2015-01-27T04:20:09.365560+00:00 smartos sata: [ID 761595 kern.info]
#011SATA disk device at port 0
2015-01-27T04:20:09.365568+00:00 smartos sata: [ID 846691 kern.info]
#011model INTEL SSDSC2BA100G3
2015-01-27T04:20:09.365574+00:00 smartos sata: [ID 693010 kern.info]
#011firmware 5DV10250
2015-01-27T04:20:09.365579+00:00 smartos sata: [ID 163988 kern.info]
#011serial number BTTV245500NH100FGN
2015-01-27T04:20:09.365586+00:00 smartos sata: [ID 594940 kern.info]
#011supported features:
2015-01-27T04:20:09.365592+00:00 smartos sata: [ID 981177 kern.info]
#011 48-bit LBA, DMA, Native Command Queueing, SMART, SMART self-test
2015-01-27T04:20:09.365597+00:00 smartos sata: [ID 996592 kern.info]
#011SATA Gen3 signaling speed (6.0Gbps)
2015-01-27T04:20:09.365602+00:00 smartos sata: [ID 349649 kern.info]
#011Supported queue depth 32
2015-01-27T04:20:09.365608+00:00 smartos sata: [ID 349649 kern.info]
#011capacity = 195371568 sectors
2015-01-27T04:20:09.415933+00:00 smartos scsi: [ID 583861 kern.info] sd1
at ahci0: target 0 lun 0
--
Ian.
-------------------------------------------
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