Multipath flapping with SAS via FCP
Hi, I have some troubles with multipath. When I add SAS disk over FCP as Storage Domain via oVirt WebUI, The first link as active, but the second is stuck as failed. Volum disk is provided from Dell Compellent via FCP, and disk is transported in SAS. multipath is flapping in all hypervisor from the same domain disk: [root@isildur-adm ~]# tail -f /var/log/messages Feb 25 11:48:21 isildur-adm kernel: device-mapper: multipath: 253:3: Failing path 8:32. Feb 25 11:48:24 isildur-adm multipathd[659460]: 36000d31003d5c2000000000000000010: sdc - tur checker reports path is up Feb 25 11:48:24 isildur-adm multipathd[659460]: 8:32: reinstated Feb 25 11:48:24 isildur-adm multipathd[659460]: 36000d31003d5c2000000000000000010: remaining active paths: 2 Feb 25 11:48:24 isildur-adm kernel: device-mapper: multipath: 253:3: Reinstating path 8:32. Feb 25 11:48:24 isildur-adm kernel: sd 1:0:1:2: alua: port group f01c state S non-preferred supports toluSNA Feb 25 11:48:24 isildur-adm kernel: sd 1:0:1:2: alua: port group f01c state S non-preferred supports toluSNA Feb 25 11:48:24 isildur-adm kernel: device-mapper: multipath: 253:3: Failing path 8:32. Feb 25 11:48:25 isildur-adm multipathd[659460]: sdc: mark as failed Feb 25 11:48:25 isildur-adm multipathd[659460]: 36000d31003d5c2000000000000000010: remaining active paths: 1 --- [root@isildur-adm ~]# multipath -ll 36000d31003d5c2000000000000000010 dm-3 COMPELNT,Compellent Vol size=1.5T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw `-+- policy='service-time 0' prio=25 status=active |- 1:0:0:2 sdb 8:16 active ready running `- 1:0:1:2 sdc 8:32 failed ready running --- VDSM generate multipath.conf like this ( I have remove commented lines for read confort ) : [root@isildur-adm ~]# cat /etc/multipath.conf # VDSM REVISION 2.0 # This file is managed by vdsm. defaults { polling_interval 5 no_path_retry 16 user_friendly_names no flush_on_last_del yes fast_io_fail_tmo 5 dev_loss_tmo 30 max_fds 4096 } blacklist { protocol "(scsi:adt|scsi:sbp)" } no_path_retry 16 } Have you some idea why this link is flapping on my two hypervisor? Thanks a lot in advance. - Benoit Chatelain
On Thu, Feb 25, 2021 at 2:29 PM Benoit Chatelain <bchatelain@cines.fr> wrote:
Hi,
I have some troubles with multipath. When I add SAS disk over FCP as Storage Domain via oVirt WebUI, The first link as active, but the second is stuck as failed.
Volum disk is provided from Dell Compellent via FCP, and disk is transported in SAS.
multipath is flapping in all hypervisor from the same domain disk:
[root@isildur-adm ~]# tail -f /var/log/messages Feb 25 11:48:21 isildur-adm kernel: device-mapper: multipath: 253:3: Failing path 8:32. Feb 25 11:48:24 isildur-adm multipathd[659460]: 36000d31003d5c2000000000000000010: sdc - tur checker reports path is up Feb 25 11:48:24 isildur-adm multipathd[659460]: 8:32: reinstated Feb 25 11:48:24 isildur-adm multipathd[659460]: 36000d31003d5c2000000000000000010: remaining active paths: 2 Feb 25 11:48:24 isildur-adm kernel: device-mapper: multipath: 253:3: Reinstating path 8:32. Feb 25 11:48:24 isildur-adm kernel: sd 1:0:1:2: alua: port group f01c state S non-preferred supports toluSNA Feb 25 11:48:24 isildur-adm kernel: sd 1:0:1:2: alua: port group f01c state S non-preferred supports toluSNA Feb 25 11:48:24 isildur-adm kernel: device-mapper: multipath: 253:3: Failing path 8:32.
Looks like the device fails immediately after it was reinstated.
Feb 25 11:48:25 isildur-adm multipathd[659460]: sdc: mark as failed Feb 25 11:48:25 isildur-adm multipathd[659460]: 36000d31003d5c2000000000000000010: remaining active paths: 1 --- [root@isildur-adm ~]# multipath -ll 36000d31003d5c2000000000000000010 dm-3 COMPELNT,Compellent Vol size=1.5T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw `-+- policy='service-time 0' prio=25 status=active |- 1:0:0:2 sdb 8:16 active ready running `- 1:0:1:2 sdc 8:32 failed ready running --- VDSM generate multipath.conf like this ( I have remove commented lines for read confort ) :
[root@isildur-adm ~]# cat /etc/multipath.conf # VDSM REVISION 2.0
# This file is managed by vdsm. defaults { polling_interval 5 no_path_retry 16 user_friendly_names no flush_on_last_del yes fast_io_fail_tmo 5 dev_loss_tmo 30 max_fds 4096 } blacklist { protocol "(scsi:adt|scsi:sbp)" }
no_path_retry 16 }
Have you some idea why this link is flapping on my two hypervisor?
Maybe Ben have an idea. You may need some configuration for that device. Not all devices have built in configuration in multipath. You can find the device details with "multipath -ll". Then look at multipathd show config And find the section related to you device. If the device is not there, you may need to add device configuration for your device. You can check with the vendor about this configuration. Nir
Hi Nir Soffer, Thank for your reply Indeed, the device fails immediately after it was reinstated. There is my 'multipathd show config' dump : defaults { verbosity 2 polling_interval 5 max_polling_interval 20 reassign_maps "no" multipath_dir "/lib64/multipath" path_selector "service-time 0" path_grouping_policy "failover" uid_attribute "ID_SERIAL" prio "const" prio_args "" features "0" path_checker "tur" alias_prefix "mpath" failback "manual" rr_min_io 1000 rr_min_io_rq 1 max_fds 4096 rr_weight "uniform" no_path_retry 16 queue_without_daemon "no" flush_on_last_del "yes" user_friendly_names "no" fast_io_fail_tmo 5 dev_loss_tmo 60 bindings_file "/etc/multipath/bindings" wwids_file "/etc/multipath/wwids" prkeys_file "/etc/multipath/prkeys" log_checker_err always all_tg_pt "no" retain_attached_hw_handler "yes" detect_prio "yes" detect_checker "yes" force_sync "no" strict_timing "no" deferred_remove "no" config_dir "/etc/multipath/conf.d" delay_watch_checks "no" delay_wait_checks "no" san_path_err_threshold "no" san_path_err_forget_rate "no" san_path_err_recovery_time "no" marginal_path_err_sample_time "no" marginal_path_err_rate_threshold "no" marginal_path_err_recheck_gap_time "no" marginal_path_double_failed_time "no" find_multipaths "on" uxsock_timeout 4000 retrigger_tries 3 retrigger_delay 10 missing_uev_wait_timeout 30 skip_kpartx "no" disable_changed_wwids ignored remove_retries 0 ghost_delay "no" find_multipaths_timeout -10 enable_foreign "" marginal_pathgroups "no" } blacklist { devnode "!^(sd[a-z]|dasd[a-z]|nvme[0-9])" wwid "36f402700f232e40026b41bd43a0812e5" protocol "(scsi:adt|scsi:sbp)" ... } blacklist_exceptions { protocol "scsi:sas" } devices { ... device { vendor "COMPELNT" product "Compellent Vol" path_grouping_policy "multibus" no_path_retry "queue" } ... } overrides { no_path_retry 16 } And there is my scsi disks (sdb & sdc disks) : [root@anarion-adm ~]# lsscsi -l [0:2:0:0] disk DELL PERC H330 Adp 4.30 /dev/sda state=running queue_depth=256 scsi_level=6 type=0 device_blocked=0 timeout=90 [1:0:0:2] disk COMPELNT Compellent Vol 0704 /dev/sdb state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30 [1:0:1:2] disk COMPELNT Compellent Vol 0704 /dev/sdc state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30 My disk configuration is present in multipath, and the DELLEMC documentation & white paper don't specifying exotics configuration for multipathd. (I'm wrong ?) I looked modules for SAS & FCP driver, they look good : [root@anarion-adm ~]# lsmod | grep sas mpt3sas 303104 4 raid_class 16384 1 mpt3sas megaraid_sas 172032 2 scsi_transport_sas 45056 1 mpt3sas [root@anarion-adm ~]# lsmod | grep fc bnx2fc 110592 0 cnic 69632 1 bnx2fc libfcoe 77824 2 qedf,bnx2fc libfc 147456 3 qedf,bnx2fc,libfcoe scsi_transport_fc 69632 3 qedf,libfc,bnx2fc Do you think my device is misconfigured? should I check on the vendor side? Another idea ? :) Regards, Benoit Chatelain
On Fri, Feb 26, 2021 at 12:07 PM Benoit Chatelain <bchatelain@cines.fr> wrote:
Hi Nir Soffer, Thank for your reply
Indeed, the device fails immediately after it was reinstated.
There is my 'multipathd show config' dump :
defaults { verbosity 2 polling_interval 5 max_polling_interval 20 reassign_maps "no" multipath_dir "/lib64/multipath" path_selector "service-time 0" path_grouping_policy "failover" uid_attribute "ID_SERIAL" prio "const" prio_args "" features "0" path_checker "tur" alias_prefix "mpath" failback "manual" rr_min_io 1000 rr_min_io_rq 1 max_fds 4096 rr_weight "uniform" no_path_retry 16 queue_without_daemon "no" flush_on_last_del "yes" user_friendly_names "no" fast_io_fail_tmo 5 dev_loss_tmo 60 bindings_file "/etc/multipath/bindings" wwids_file "/etc/multipath/wwids" prkeys_file "/etc/multipath/prkeys" log_checker_err always all_tg_pt "no" retain_attached_hw_handler "yes" detect_prio "yes" detect_checker "yes" force_sync "no" strict_timing "no" deferred_remove "no" config_dir "/etc/multipath/conf.d" delay_watch_checks "no" delay_wait_checks "no" san_path_err_threshold "no" san_path_err_forget_rate "no" san_path_err_recovery_time "no" marginal_path_err_sample_time "no" marginal_path_err_rate_threshold "no" marginal_path_err_recheck_gap_time "no" marginal_path_double_failed_time "no" find_multipaths "on" uxsock_timeout 4000 retrigger_tries 3 retrigger_delay 10 missing_uev_wait_timeout 30 skip_kpartx "no" disable_changed_wwids ignored remove_retries 0 ghost_delay "no" find_multipaths_timeout -10 enable_foreign "" marginal_pathgroups "no" } blacklist { devnode "!^(sd[a-z]|dasd[a-z]|nvme[0-9])" wwid "36f402700f232e40026b41bd43a0812e5" protocol "(scsi:adt|scsi:sbp)" ... } blacklist_exceptions { protocol "scsi:sas" } devices { ... device { vendor "COMPELNT" product "Compellent Vol" path_grouping_policy "multibus" no_path_retry "queue" } ... } overrides { no_path_retry 16 }
And there is my scsi disks (sdb & sdc disks) :
[root@anarion-adm ~]# lsscsi -l [0:2:0:0] disk DELL PERC H330 Adp 4.30 /dev/sda state=running queue_depth=256 scsi_level=6 type=0 device_blocked=0 timeout=90 [1:0:0:2] disk COMPELNT Compellent Vol 0704 /dev/sdb state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30 [1:0:1:2] disk COMPELNT Compellent Vol 0704 /dev/sdc state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30
My disk configuration is present in multipath, and the DELLEMC documentation & white paper don't specifying exotics configuration for multipathd. (I'm wrong ?)
I looked modules for SAS & FCP driver, they look good :
[root@anarion-adm ~]# lsmod | grep sas mpt3sas 303104 4 raid_class 16384 1 mpt3sas megaraid_sas 172032 2 scsi_transport_sas 45056 1 mpt3sas
[root@anarion-adm ~]# lsmod | grep fc bnx2fc 110592 0 cnic 69632 1 bnx2fc libfcoe 77824 2 qedf,bnx2fc libfc 147456 3 qedf,bnx2fc,libfcoe scsi_transport_fc 69632 3 qedf,libfc,bnx2fc
Do you think my device is misconfigured? should I check on the vendor side? Another idea ? :)
I guess this is related to exposing a FC device via SAS, not sure how this is done and why. I hope Ben (RHEL multipath maintainer) can help with this. Nir
On Fri, Feb 26, 2021 at 05:29:50PM +0200, Nir Soffer wrote:
On Fri, Feb 26, 2021 at 12:07 PM Benoit Chatelain <bchatelain@cines.fr> wrote:
Hi Nir Soffer, Thank for your reply
Indeed, the device fails immediately after it was reinstated.
There is my 'multipathd show config' dump :
defaults { verbosity 2 polling_interval 5 max_polling_interval 20 reassign_maps "no" multipath_dir "/lib64/multipath" path_selector "service-time 0" path_grouping_policy "failover" uid_attribute "ID_SERIAL" prio "const" prio_args "" features "0" path_checker "tur" alias_prefix "mpath" failback "manual" rr_min_io 1000 rr_min_io_rq 1 max_fds 4096 rr_weight "uniform" no_path_retry 16 queue_without_daemon "no" flush_on_last_del "yes" user_friendly_names "no" fast_io_fail_tmo 5 dev_loss_tmo 60 bindings_file "/etc/multipath/bindings" wwids_file "/etc/multipath/wwids" prkeys_file "/etc/multipath/prkeys" log_checker_err always all_tg_pt "no" retain_attached_hw_handler "yes" detect_prio "yes" detect_checker "yes" force_sync "no" strict_timing "no" deferred_remove "no" config_dir "/etc/multipath/conf.d" delay_watch_checks "no" delay_wait_checks "no" san_path_err_threshold "no" san_path_err_forget_rate "no" san_path_err_recovery_time "no" marginal_path_err_sample_time "no" marginal_path_err_rate_threshold "no" marginal_path_err_recheck_gap_time "no" marginal_path_double_failed_time "no" find_multipaths "on" uxsock_timeout 4000 retrigger_tries 3 retrigger_delay 10 missing_uev_wait_timeout 30 skip_kpartx "no" disable_changed_wwids ignored remove_retries 0 ghost_delay "no" find_multipaths_timeout -10 enable_foreign "" marginal_pathgroups "no" } blacklist { devnode "!^(sd[a-z]|dasd[a-z]|nvme[0-9])" wwid "36f402700f232e40026b41bd43a0812e5" protocol "(scsi:adt|scsi:sbp)" ... } blacklist_exceptions { protocol "scsi:sas" } devices { ... device { vendor "COMPELNT" product "Compellent Vol" path_grouping_policy "multibus" no_path_retry "queue" } ... } overrides { no_path_retry 16 }
And there is my scsi disks (sdb & sdc disks) :
[root@anarion-adm ~]# lsscsi -l [0:2:0:0] disk DELL PERC H330 Adp 4.30 /dev/sda state=running queue_depth=256 scsi_level=6 type=0 device_blocked=0 timeout=90 [1:0:0:2] disk COMPELNT Compellent Vol 0704 /dev/sdb state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30 [1:0:1:2] disk COMPELNT Compellent Vol 0704 /dev/sdc state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30
My disk configuration is present in multipath, and the DELLEMC documentation & white paper don't specifying exotics configuration for multipathd. (I'm wrong ?)
I looked modules for SAS & FCP driver, they look good :
[root@anarion-adm ~]# lsmod | grep sas mpt3sas 303104 4 raid_class 16384 1 mpt3sas megaraid_sas 172032 2 scsi_transport_sas 45056 1 mpt3sas
[root@anarion-adm ~]# lsmod | grep fc bnx2fc 110592 0 cnic 69632 1 bnx2fc libfcoe 77824 2 qedf,bnx2fc libfc 147456 3 qedf,bnx2fc,libfcoe scsi_transport_fc 69632 3 qedf,libfc,bnx2fc
Do you think my device is misconfigured? should I check on the vendor side? Another idea ? :)
I guess this is related to exposing a FC device via SAS, not sure how this is done and why.
I hope Ben (RHEL multipath maintainer) can help with this.
The issue here is that the device appears to be advertising itself as ready when it responds to the SCSI Test Unit Ready command. However, it is not actually able to handle IO sent to it. To make multipath stop flapping, you can add path_checker directio to the devices configuration for this device. That will make multipath send a read request to the device to determine if it is usable. This should fail, meaning that the device will stay in the failed state. As to why the device isn't able to handle IO, looking at the log messages: Feb 25 11:48:24 isildur-adm kernel: sd 1:0:1:2: alua: port group f01c state S non-preferred supports toluSNA State "S" is standby. The odd thing is that unless I'm mistaken, SCSI devices in the Standby state should respond to TUR command with with "Not Ready", which should either result in a DOWN or GHOST state in multipath, depending on the reason why the device is not ready. Could you try manually issuing a tur command to the scsi device # sg_turs /dev/sdc # echo $? assuming that sdc is your problem device. If the result is 0, then the device really is responding that it's ready while actually being in the standby state. If the result is 2 (Not Ready), then there is something wrong with how multpath is interpreting the TUR command sense buffer. -Ben
Nir
Hello Ben, I have make some test with devices in multipath.conf, directio doesn't work. But, I had e-mail from dm-devel@redhat.com -Xose Vazquez Perez, with some instructions and it work's. in multipath.conf, add 'path_grouping_policy "group_by_prio"' to device devices { device { vendor "COMPELNT" product "Compellent Vol" path_grouping_policy "group_by_prio" prio "alua" failback "immediate" no_path_retry 30 } } Thank you. Regards, Benoit Chatelain ----- Mail original ----- De: "Benjamin Marzinski" <bmarzins@redhat.com> À: "Nir Soffer" <nsoffer@redhat.com> Cc: "Benoit Chatelain" <bchatelain@cines.fr>, "users" <users@ovirt.org> Envoyé: Lundi 1 Mars 2021 21:15:21 Objet: Re: [ovirt-users] Re: Multipath flapping with SAS via FCP On Fri, Feb 26, 2021 at 05:29:50PM +0200, Nir Soffer wrote:
On Fri, Feb 26, 2021 at 12:07 PM Benoit Chatelain <bchatelain@cines.fr> wrote:
Hi Nir Soffer, Thank for your reply
Indeed, the device fails immediately after it was reinstated.
There is my 'multipathd show config' dump :
defaults { verbosity 2 polling_interval 5 max_polling_interval 20 reassign_maps "no" multipath_dir "/lib64/multipath" path_selector "service-time 0" path_grouping_policy "failover" uid_attribute "ID_SERIAL" prio "const" prio_args "" features "0" path_checker "tur" alias_prefix "mpath" failback "manual" rr_min_io 1000 rr_min_io_rq 1 max_fds 4096 rr_weight "uniform" no_path_retry 16 queue_without_daemon "no" flush_on_last_del "yes" user_friendly_names "no" fast_io_fail_tmo 5 dev_loss_tmo 60 bindings_file "/etc/multipath/bindings" wwids_file "/etc/multipath/wwids" prkeys_file "/etc/multipath/prkeys" log_checker_err always all_tg_pt "no" retain_attached_hw_handler "yes" detect_prio "yes" detect_checker "yes" force_sync "no" strict_timing "no" deferred_remove "no" config_dir "/etc/multipath/conf.d" delay_watch_checks "no" delay_wait_checks "no" san_path_err_threshold "no" san_path_err_forget_rate "no" san_path_err_recovery_time "no" marginal_path_err_sample_time "no" marginal_path_err_rate_threshold "no" marginal_path_err_recheck_gap_time "no" marginal_path_double_failed_time "no" find_multipaths "on" uxsock_timeout 4000 retrigger_tries 3 retrigger_delay 10 missing_uev_wait_timeout 30 skip_kpartx "no" disable_changed_wwids ignored remove_retries 0 ghost_delay "no" find_multipaths_timeout -10 enable_foreign "" marginal_pathgroups "no" } blacklist { devnode "!^(sd[a-z]|dasd[a-z]|nvme[0-9])" wwid "36f402700f232e40026b41bd43a0812e5" protocol "(scsi:adt|scsi:sbp)" ... } blacklist_exceptions { protocol "scsi:sas" } devices { ... device { vendor "COMPELNT" product "Compellent Vol" path_grouping_policy "multibus" no_path_retry "queue" } ... } overrides { no_path_retry 16 }
And there is my scsi disks (sdb & sdc disks) :
[root@anarion-adm ~]# lsscsi -l [0:2:0:0] disk DELL PERC H330 Adp 4.30 /dev/sda state=running queue_depth=256 scsi_level=6 type=0 device_blocked=0 timeout=90 [1:0:0:2] disk COMPELNT Compellent Vol 0704 /dev/sdb state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30 [1:0:1:2] disk COMPELNT Compellent Vol 0704 /dev/sdc state=running queue_depth=254 scsi_level=6 type=0 device_blocked=0 timeout=30
My disk configuration is present in multipath, and the DELLEMC documentation & white paper don't specifying exotics configuration for multipathd. (I'm wrong ?)
I looked modules for SAS & FCP driver, they look good :
[root@anarion-adm ~]# lsmod | grep sas mpt3sas 303104 4 raid_class 16384 1 mpt3sas megaraid_sas 172032 2 scsi_transport_sas 45056 1 mpt3sas
[root@anarion-adm ~]# lsmod | grep fc bnx2fc 110592 0 cnic 69632 1 bnx2fc libfcoe 77824 2 qedf,bnx2fc libfc 147456 3 qedf,bnx2fc,libfcoe scsi_transport_fc 69632 3 qedf,libfc,bnx2fc
Do you think my device is misconfigured? should I check on the vendor side? Another idea ? :)
I guess this is related to exposing a FC device via SAS, not sure how this is done and why.
I hope Ben (RHEL multipath maintainer) can help with this.
The issue here is that the device appears to be advertising itself as ready when it responds to the SCSI Test Unit Ready command. However, it is not actually able to handle IO sent to it. To make multipath stop flapping, you can add path_checker directio to the devices configuration for this device. That will make multipath send a read request to the device to determine if it is usable. This should fail, meaning that the device will stay in the failed state. As to why the device isn't able to handle IO, looking at the log messages: Feb 25 11:48:24 isildur-adm kernel: sd 1:0:1:2: alua: port group f01c state S non-preferred supports toluSNA State "S" is standby. The odd thing is that unless I'm mistaken, SCSI devices in the Standby state should respond to TUR command with with "Not Ready", which should either result in a DOWN or GHOST state in multipath, depending on the reason why the device is not ready. Could you try manually issuing a tur command to the scsi device # sg_turs /dev/sdc # echo $? assuming that sdc is your problem device. If the result is 0, then the device really is responding that it's ready while actually being in the standby state. If the result is 2 (Not Ready), then there is something wrong with how multpath is interpreting the TUR command sense buffer. -Ben
Nir
participants (4)
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bchatelain＠cines.fr -
Benjamin Marzinski -
Benoit Chatelain
-
Nir Soffer