* Unable to set group_thread_cnt using mdadm.conf
@ 2025-10-17 14:07 Franco Martelli
2025-10-20 14:40 ` Xiao Ni
0 siblings, 1 reply; 5+ messages in thread
From: Franco Martelli @ 2025-10-17 14:07 UTC (permalink / raw)
To: linux-raid; +Cc: xni, ncroxon, mtkaczyk
Hello,
I've a RAID5 array on Debian 13:
~$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [linear] [raid0] [raid1] [raid10]
md0 : active raid5 sda1[0] sdc1[2] sdd1[3](S) sdb1[1]
1953258496 blocks super 1.2 level 5, 512k chunk, algorithm 2
[3/3] [UUU]
unused devices: <none>
~# mdadm --version
mdadm - v4.4 - 2024-11-07 - Debian 4.4-11
the issue is that I can't set group_thread_cnt if I use the syntax
described in mdadm.conf(5) man-page:
…
SYSFS name=/dev/md/raid5 group_thread_cnt=4 sync_speed_max=1000000
SYSFS uuid=bead5eb6:31c17a27:da120ba2:7dfda40d group_thread_cnt=4
sync_speed_max=1000000
my "mdadm.conf" is:
~$ grep -v '^#' /etc/mdadm/mdadm.conf
HOMEHOST <system>
MAILADDR root
ARRAY /dev/md/0 metadata=1.2 UUID=8bdf78b9:4cad434c:3a30392d:8463c7e0
spares=1
SYSFS name=/dev/md/0 group_thread_cnt=8
SYSFS uuid=8bdf78b9:4cad434c:3a30392d:8463c7e0 sync_speed_max=1000000
after I makes changes to the file "mdadm.conf" I rebuild the initramfs
image file and reboot. The thing that seems strange to me is that the
other item I set (sync_speed_max) is changed accordingly, only
"group_thread_cnt" fails to set (it's always ==0):
~$ cat /sys/block/md0/md/group_thread_cnt
0
~$ cat /sys/block/md0/md/sync_speed_max
1000000 (system)
Why "sync_speed_max" is set while "group_thread_cnt" it is not? Any clue?
Thanks in advance, kind regards.
--
Franco Martelli
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: Unable to set group_thread_cnt using mdadm.conf 2025-10-17 14:07 Unable to set group_thread_cnt using mdadm.conf Franco Martelli @ 2025-10-20 14:40 ` Xiao Ni 2025-10-20 19:22 ` Franco Martelli 0 siblings, 1 reply; 5+ messages in thread From: Xiao Ni @ 2025-10-20 14:40 UTC (permalink / raw) To: Franco Martelli; +Cc: linux-raid, ncroxon, mtkaczyk On Fri, Oct 17, 2025 at 10:07 PM Franco Martelli <martellif67@gmail.com> wrote: > > Hello, > > I've a RAID5 array on Debian 13: > > ~$ cat /proc/mdstat > Personalities : [raid6] [raid5] [raid4] [linear] [raid0] [raid1] [raid10] > md0 : active raid5 sda1[0] sdc1[2] sdd1[3](S) sdb1[1] > 1953258496 blocks super 1.2 level 5, 512k chunk, algorithm 2 > [3/3] [UUU] > > unused devices: <none> > > ~# mdadm --version > mdadm - v4.4 - 2024-11-07 - Debian 4.4-11 > > the issue is that I can't set group_thread_cnt if I use the syntax > described in mdadm.conf(5) man-page: > > … > SYSFS name=/dev/md/raid5 group_thread_cnt=4 sync_speed_max=1000000 > SYSFS uuid=bead5eb6:31c17a27:da120ba2:7dfda40d group_thread_cnt=4 > sync_speed_max=1000000 > > my "mdadm.conf" is: > > ~$ grep -v '^#' /etc/mdadm/mdadm.conf > > > HOMEHOST <system> > > MAILADDR root > > ARRAY /dev/md/0 metadata=1.2 UUID=8bdf78b9:4cad434c:3a30392d:8463c7e0 > spares=1 > > > SYSFS name=/dev/md/0 group_thread_cnt=8 > SYSFS uuid=8bdf78b9:4cad434c:3a30392d:8463c7e0 sync_speed_max=1000000 > > > after I makes changes to the file "mdadm.conf" I rebuild the initramfs > image file and reboot. The thing that seems strange to me is that the > other item I set (sync_speed_max) is changed accordingly, only > "group_thread_cnt" fails to set (it's always ==0): > > ~$ cat /sys/block/md0/md/group_thread_cnt > 0 > ~$ cat /sys/block/md0/md/sync_speed_max > 1000000 (system) > > Why "sync_speed_max" is set while "group_thread_cnt" it is not? Any clue? Hi Franco The sync_speed_max should not be set too. Because it still shows "system" rather than "local". I tried in my environment. It indeed has a problem if you specify uuid in conf file to set sysfs value. This is my conf: cat /etc/mdadm.conf ARRAY /dev/md/0 metadata=1.2 UUID=689642b7:fa1e5cf2:82c6c527:ca37716f SYSFS name=/dev/md/0 sync_speed_max=5000 group_thread_cnt=8 After assembling by command `mdadm -As`: [root@ mdadm]# cat /sys/block/md0/md/group_thread_cnt 8 [root@ mdadm]# cat /sys/block/md0/md/sync_speed_max 5000 (local) If I specify uuid in the second line of the conf file, it can't work. Because the uuid read from the device doesn't match with the conf file. It should be the problem of big-endian and little-endian. I'm looking at this problem. But in your conf, the group thread cnt should be set successfully. What's your command to assemble the array? Can you stop the array and assemble it after boot. Regards Xiao > > Thanks in advance, kind regards. > -- > Franco Martelli > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Unable to set group_thread_cnt using mdadm.conf 2025-10-20 14:40 ` Xiao Ni @ 2025-10-20 19:22 ` Franco Martelli 2025-10-21 0:33 ` Xiao Ni 0 siblings, 1 reply; 5+ messages in thread From: Franco Martelli @ 2025-10-20 19:22 UTC (permalink / raw) To: Xiao Ni; +Cc: linux-raid, ncroxon, mtkaczyk On 20/10/25 at 16:40, Xiao Ni wrote: > On Fri, Oct 17, 2025 at 10:07 PM Franco Martelli <martellif67@gmail.com> wrote: >> >> Hello, >> >> I've a RAID5 array on Debian 13: >> >> ~$ cat /proc/mdstat >> Personalities : [raid6] [raid5] [raid4] [linear] [raid0] [raid1] [raid10] >> md0 : active raid5 sda1[0] sdc1[2] sdd1[3](S) sdb1[1] >> 1953258496 blocks super 1.2 level 5, 512k chunk, algorithm 2 >> [3/3] [UUU] >> >> unused devices: <none> >> >> ~# mdadm --version >> mdadm - v4.4 - 2024-11-07 - Debian 4.4-11 >> >> the issue is that I can't set group_thread_cnt if I use the syntax >> described in mdadm.conf(5) man-page: >> >> … >> SYSFS name=/dev/md/raid5 group_thread_cnt=4 sync_speed_max=1000000 >> SYSFS uuid=bead5eb6:31c17a27:da120ba2:7dfda40d group_thread_cnt=4 >> sync_speed_max=1000000 >> >> my "mdadm.conf" is: >> >> ~$ grep -v '^#' /etc/mdadm/mdadm.conf >> >> >> HOMEHOST <system> >> >> MAILADDR root >> >> ARRAY /dev/md/0 metadata=1.2 UUID=8bdf78b9:4cad434c:3a30392d:8463c7e0 >> spares=1 >> >> >> SYSFS name=/dev/md/0 group_thread_cnt=8 >> SYSFS uuid=8bdf78b9:4cad434c:3a30392d:8463c7e0 sync_speed_max=1000000 >> >> >> after I makes changes to the file "mdadm.conf" I rebuild the initramfs >> image file and reboot. The thing that seems strange to me is that the >> other item I set (sync_speed_max) is changed accordingly, only >> "group_thread_cnt" fails to set (it's always ==0): >> >> ~$ cat /sys/block/md0/md/group_thread_cnt >> 0 >> ~$ cat /sys/block/md0/md/sync_speed_max >> 1000000 (system) >> >> Why "sync_speed_max" is set while "group_thread_cnt" it is not? Any clue? > > Hi Franco > > The sync_speed_max should not be set too. Because it still shows > "system" rather than "local". I tried in my environment. It indeed has > a problem if you specify uuid in conf file to set sysfs value. This is > my conf: Hi Xiao, Yes, it's correct, I cannot set sync_speed_max maybe it reflects the setting of: ~$ cat /etc/sysctl.d/md0.conf dev.raid.speed_limit_max = 1000000 I don't know, I guess… > > cat /etc/mdadm.conf > ARRAY /dev/md/0 metadata=1.2 UUID=689642b7:fa1e5cf2:82c6c527:ca37716f > SYSFS name=/dev/md/0 sync_speed_max=5000 group_thread_cnt=8 > > After assembling by command `mdadm -As`: > [root@ mdadm]# cat /sys/block/md0/md/group_thread_cnt > 8 > [root@ mdadm]# cat /sys/block/md0/md/sync_speed_max > 5000 (local) > > If I specify uuid in the second line of the conf file, it can't work. > Because the uuid read from the device doesn't match with the conf > file. It should be the problem of big-endian and little-endian. I'm > looking at this problem. > > But in your conf, the group thread cnt should be set successfully. > What's your command to assemble the array? Can you stop the array and > assemble it after boot. my mdadm.conf now is: ~$ grep -v '^#' /etc/mdadm/mdadm.conf HOMEHOST <system> MAILADDR root ARRAY /dev/md/0 metadata=1.2 UUID=8bdf78b9:4cad434c:3a30392d:8463c7e0 spares=1 SYSFS name=/dev/md/0 sync_speed_max=5000000 group_thread_cnt=8 I rebuild the initramfs image file: ~# update-initramfs -uk all update-initramfs: Generating /boot/initrd.img-6.12.48+deb13-amd64 update-initramfs: Generating /boot/initrd.img-6.12.48 mdadm files in the initramfs file are: ~# lsinitramfs /boot/initrd.img-6.12.48 |grep mdadm etc/mdadm etc/mdadm/mdadm.conf etc/modprobe.d/mdadm.conf scripts/local-block/mdadm scripts/local-bottom/mdadm usr/sbin/mdadm and then I rebooted the system, I cannot set group_thread_cnt: ~$ cat /sys/block/md0/md/sync_speed_max 1000000 (system) ~$ cat /sys/block/md0/md/group_thread_cnt 0 I cannot stop the array since my root filesystem resides on it. The command that Debian 13 Trixie uses to assemble the array is: ~$ ps -wax|grep mdadm 543 ? Ss 0:00 /usr/sbin/mdadm --monitor --scan FYI the topology of the storage on my system is: PCI [ahci] 00:11.0 SATA controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 SATA Controller [AHCI mode] (rev 40) ├scsi 0:0:0:0 ATA ST1000DM003-1CH1 {Z1D93ZHJ} │└sda 931.51g [8:0] Partitioned (dos) │ └sda1 931.51g [8:1] MD raid5 (0/3) (w/ sdd1,sdc1,sdb1) in_sync 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} │ │ PV LVM2_member 1,82t used, 0 free {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} │ └VG ld0 1,82t 0 free {BUUpNE-w0IY-Ut2I-OmiZ-err7-zXLX-F0VmjU} │ ├dm-6 1.67t [253:6] LV data ext4 {29ed4bd3-f546-4781-988c-39f853276492} │ ├dm-1 27.94g [253:1] LV lv1 ext4 {fa251689-956d-4a3c-b60c-0ab92ac51488} │ ├dm-2 27.94g [253:2] LV lv2 ext4 {4baf8453-6525-4b72-aade-25de240ac4f4} │ ├dm-3 27.94g [253:3] LV lv3 ext4 {9ad082fd-d9fb-4ddc-b3e8-a39753480319} │ │└Mounted as /dev/mapper/ld0-lv3 @ / │ ├dm-4 27.94g [253:4] LV lv4 ext4 {6cbd93ab-0def-4a56-8270-176c66588c45} │ ├dm-5 27.94g [253:5] LV lv5 ext4 {665d8145-786a-461b-a4c1-7155156c40be} │ └dm-0 9.31g [253:0] LV swap swap {f3859a53-eb70-4a7b-ac94-93433b72a723} ├scsi 1:0:0:0 ATA ST1000DM003-1CH1 {Z1D8ZJ1H} │└sdb 931.51g [8:16] Partitioned (dos) │ └sdb1 931.51g [8:17] MD raid5 (1/3) (w/ sdd1,sdc1,sda1) in_sync 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} │ PV LVM2_member 1,82t used, 0 free {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} ├scsi 2:0:0:0 ATA ST1000DM003-1CH1 {Z1D94DF3} │└sdc 931.51g [8:32] Partitioned (dos) │ └sdc1 931.51g [8:33] MD raid5 (2/3) (w/ sdd1,sdb1,sda1) in_sync 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} │ PV LVM2_member 1,82t used, 0 free {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} ├scsi 3:0:0:0 ATA ST1000DM003-1CH1 {Z1D94DF5} │└sdd 931.51g [8:48] Partitioned (dos) │ └sdd1 931.51g [8:49] MD raid5 (none/3) (w/ sdc1,sdb1,sda1) spare 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} │ PV LVM2_member 1,82t used, 0 free {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} └scsi 4:0:0:0 ASUS BW-16D1HT {K9GDBBA5248} └sr0 1.00g [11:0] Empty/Unknown PCI [ahci] 04:00.0 SATA controller: ASMedia Technology Inc. ASM1062 Serial ATA Controller (rev 01) └scsi 5:x:x:x [Empty] Thank you again, kind regards. -- Franco Martelli ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Unable to set group_thread_cnt using mdadm.conf 2025-10-20 19:22 ` Franco Martelli @ 2025-10-21 0:33 ` Xiao Ni 0 siblings, 0 replies; 5+ messages in thread From: Xiao Ni @ 2025-10-21 0:33 UTC (permalink / raw) To: Franco Martelli; +Cc: linux-raid, ncroxon, mtkaczyk On Tue, Oct 21, 2025 at 3:22 AM Franco Martelli <martellif67@gmail.com> wrote: > > On 20/10/25 at 16:40, Xiao Ni wrote: > > On Fri, Oct 17, 2025 at 10:07 PM Franco Martelli <martellif67@gmail.com> wrote: > >> > >> Hello, > >> > >> I've a RAID5 array on Debian 13: > >> > >> ~$ cat /proc/mdstat > >> Personalities : [raid6] [raid5] [raid4] [linear] [raid0] [raid1] [raid10] > >> md0 : active raid5 sda1[0] sdc1[2] sdd1[3](S) sdb1[1] > >> 1953258496 blocks super 1.2 level 5, 512k chunk, algorithm 2 > >> [3/3] [UUU] > >> > >> unused devices: <none> > >> > >> ~# mdadm --version > >> mdadm - v4.4 - 2024-11-07 - Debian 4.4-11 > >> > >> the issue is that I can't set group_thread_cnt if I use the syntax > >> described in mdadm.conf(5) man-page: > >> > >> … > >> SYSFS name=/dev/md/raid5 group_thread_cnt=4 sync_speed_max=1000000 > >> SYSFS uuid=bead5eb6:31c17a27:da120ba2:7dfda40d group_thread_cnt=4 > >> sync_speed_max=1000000 > >> > >> my "mdadm.conf" is: > >> > >> ~$ grep -v '^#' /etc/mdadm/mdadm.conf > >> > >> > >> HOMEHOST <system> > >> > >> MAILADDR root > >> > >> ARRAY /dev/md/0 metadata=1.2 UUID=8bdf78b9:4cad434c:3a30392d:8463c7e0 > >> spares=1 > >> > >> > >> SYSFS name=/dev/md/0 group_thread_cnt=8 > >> SYSFS uuid=8bdf78b9:4cad434c:3a30392d:8463c7e0 sync_speed_max=1000000 > >> > >> > >> after I makes changes to the file "mdadm.conf" I rebuild the initramfs > >> image file and reboot. The thing that seems strange to me is that the > >> other item I set (sync_speed_max) is changed accordingly, only > >> "group_thread_cnt" fails to set (it's always ==0): > >> > >> ~$ cat /sys/block/md0/md/group_thread_cnt > >> 0 > >> ~$ cat /sys/block/md0/md/sync_speed_max > >> 1000000 (system) > >> > >> Why "sync_speed_max" is set while "group_thread_cnt" it is not? Any clue? > > > > Hi Franco > > > > The sync_speed_max should not be set too. Because it still shows > > "system" rather than "local". I tried in my environment. It indeed has > > a problem if you specify uuid in conf file to set sysfs value. This is > > my conf: > > Hi Xiao, > > Yes, it's correct, I cannot set sync_speed_max maybe it reflects the > setting of: > > ~$ cat /etc/sysctl.d/md0.conf > dev.raid.speed_limit_max = 1000000 > > I don't know, I guess… > > > > > cat /etc/mdadm.conf > > ARRAY /dev/md/0 metadata=1.2 UUID=689642b7:fa1e5cf2:82c6c527:ca37716f > > SYSFS name=/dev/md/0 sync_speed_max=5000 group_thread_cnt=8 > > > > After assembling by command `mdadm -As`: > > [root@ mdadm]# cat /sys/block/md0/md/group_thread_cnt > > 8 > > [root@ mdadm]# cat /sys/block/md0/md/sync_speed_max > > 5000 (local) > > > > If I specify uuid in the second line of the conf file, it can't work. > > Because the uuid read from the device doesn't match with the conf > > file. It should be the problem of big-endian and little-endian. I'm > > looking at this problem. > > > > But in your conf, the group thread cnt should be set successfully. > > What's your command to assemble the array? Can you stop the array and > > assemble it after boot. > > my mdadm.conf now is: > > ~$ grep -v '^#' /etc/mdadm/mdadm.conf > > > HOMEHOST <system> > > MAILADDR root > > ARRAY /dev/md/0 metadata=1.2 UUID=8bdf78b9:4cad434c:3a30392d:8463c7e0 > spares=1 > > > SYSFS name=/dev/md/0 sync_speed_max=5000000 group_thread_cnt=8 > > > I rebuild the initramfs image file: > > ~# update-initramfs -uk all > update-initramfs: Generating /boot/initrd.img-6.12.48+deb13-amd64 > update-initramfs: Generating /boot/initrd.img-6.12.48 > > > mdadm files in the initramfs file are: > > ~# lsinitramfs /boot/initrd.img-6.12.48 |grep mdadm > etc/mdadm > etc/mdadm/mdadm.conf > etc/modprobe.d/mdadm.conf > scripts/local-block/mdadm > scripts/local-bottom/mdadm > usr/sbin/mdadm > > > and then I rebooted the system, I cannot set group_thread_cnt: > > ~$ cat /sys/block/md0/md/sync_speed_max > 1000000 (system) > ~$ cat /sys/block/md0/md/group_thread_cnt > 0 > > > I cannot stop the array since my root filesystem resides on it. The > command that Debian 13 Trixie uses to assemble the array is: > > ~$ ps -wax|grep mdadm > 543 ? Ss 0:00 /usr/sbin/mdadm --monitor --scan > > > FYI the topology of the storage on my system is: > > PCI [ahci] 00:11.0 SATA controller: Advanced Micro Devices, Inc. > [AMD/ATI] SB7x0/SB8x0/SB9x0 SATA Controller [AHCI mode] (rev 40) > ├scsi 0:0:0:0 ATA ST1000DM003-1CH1 {Z1D93ZHJ} > │└sda 931.51g [8:0] Partitioned (dos) > │ └sda1 931.51g [8:1] MD raid5 (0/3) (w/ sdd1,sdc1,sdb1) in_sync > 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} > │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk > {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} > │ │ PV LVM2_member 1,82t used, 0 free > {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} > │ └VG ld0 1,82t 0 free {BUUpNE-w0IY-Ut2I-OmiZ-err7-zXLX-F0VmjU} > │ ├dm-6 1.67t [253:6] LV data ext4 {29ed4bd3-f546-4781-988c-39f853276492} > │ ├dm-1 27.94g [253:1] LV lv1 ext4 {fa251689-956d-4a3c-b60c-0ab92ac51488} > │ ├dm-2 27.94g [253:2] LV lv2 ext4 {4baf8453-6525-4b72-aade-25de240ac4f4} > │ ├dm-3 27.94g [253:3] LV lv3 ext4 {9ad082fd-d9fb-4ddc-b3e8-a39753480319} > │ │└Mounted as /dev/mapper/ld0-lv3 @ / > │ ├dm-4 27.94g [253:4] LV lv4 ext4 {6cbd93ab-0def-4a56-8270-176c66588c45} > │ ├dm-5 27.94g [253:5] LV lv5 ext4 {665d8145-786a-461b-a4c1-7155156c40be} > │ └dm-0 9.31g [253:0] LV swap swap {f3859a53-eb70-4a7b-ac94-93433b72a723} > ├scsi 1:0:0:0 ATA ST1000DM003-1CH1 {Z1D8ZJ1H} > │└sdb 931.51g [8:16] Partitioned (dos) > │ └sdb1 931.51g [8:17] MD raid5 (1/3) (w/ sdd1,sdc1,sda1) in_sync > 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} > │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk > {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} > │ PV LVM2_member 1,82t used, 0 free > {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} > ├scsi 2:0:0:0 ATA ST1000DM003-1CH1 {Z1D94DF3} > │└sdc 931.51g [8:32] Partitioned (dos) > │ └sdc1 931.51g [8:33] MD raid5 (2/3) (w/ sdd1,sdb1,sda1) in_sync > 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} > │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk > {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} > │ PV LVM2_member 1,82t used, 0 free > {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} > ├scsi 3:0:0:0 ATA ST1000DM003-1CH1 {Z1D94DF5} > │└sdd 931.51g [8:48] Partitioned (dos) > │ └sdd1 931.51g [8:49] MD raid5 (none/3) (w/ sdc1,sdb1,sda1) spare > 'itek:0' {8bdf78b9-4cad-434c-3a30-392d8463c7e0} > │ └md0 1.82t [9:0] MD v1.2 raid5 (3) clean, 512k Chunk > {8bdf78b9:-4cad-43:4c-3a30-:392d8463c7e0} > │ PV LVM2_member 1,82t used, 0 free > {6HMlpl-ZLKi-4JOP-DU9i-aiZh-7IoH-Dd1Hoy} > └scsi 4:0:0:0 ASUS BW-16D1HT {K9GDBBA5248} > └sr0 1.00g [11:0] Empty/Unknown > PCI [ahci] 04:00.0 SATA controller: ASMedia Technology Inc. ASM1062 > Serial ATA Controller (rev 01) > └scsi 5:x:x:x [Empty] I c, thanks for the detailed information. The array is assembled during boot by udev rule which runs `mdadm -I` command. I looked at the codes. mdadm doesn't support setting sysfs values through this way. Maybe the author missed this part. He was only concerned about imsm array. In my environment: mdadm -Ss cat /etc/mdadm.conf ARRAY /dev/md/0 metadata=1.2 UUID=689642b7:fa1e5cf2:82c6c527:ca37716f SYSFS name=/dev/md/0 sync_speed_max=5000 group_thread_cnt=8 mdadm -I /dev/loop0 mdadm -I /dev/loop1 mdadm -I /dev/loop2 [root@ mdadm]# cat /sys/block/md0/md/group_thread_cnt 0 [root@ mdadm]# cat /sys/block/md0/md/sync_speed_max 200000 (system) So it indeed doesn't work now. I'll fix this. And I've filed a new issue at https://github.com/md-raid-utilities/mdadm/issues/208. Regards Xiao > > > Thank you again, kind regards. > -- > Franco Martelli > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Unable to set group_thread_cnt using mdadm.conf
@ 2025-10-14 19:53 Franco Martelli
0 siblings, 0 replies; 5+ messages in thread
From: Franco Martelli @ 2025-10-14 19:53 UTC (permalink / raw)
To: linux-raid
Hello,
I've a RAID5 array on Debian 13:
~$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [linear] [raid0] [raid1] [raid10]
md0 : active raid5 sda1[0] sdc1[2] sdd1[3](S) sdb1[1]
1953258496 blocks super 1.2 level 5, 512k chunk, algorithm 2
[3/3] [UUU]
unused devices: <none>
~# mdadm --version
mdadm - v4.4 - 2024-11-07 - Debian 4.4-11
the issue is that I can't set group_thread_cnt if I use the syntax
described in mdadm.conf(5) man-page:
…
SYSFS name=/dev/md/raid5 group_thread_cnt=4 sync_speed_max=1000000
SYSFS uuid=bead5eb6:31c17a27:da120ba2:7dfda40d group_thread_cnt=4
sync_speed_max=1000000
my "mdadm.conf" is:
~$ cat /etc/mdadm/mdadm.conf | grep -v "#"
HOMEHOST <system>
MAILADDR root
ARRAY /dev/md/0 metadata=1.2 UUID=8bdf78b9:4cad434c:3a30392d:8463c7e0
spares=1
SYSFS name=/dev/md/0 group_thread_cnt=8
SYSFS uuid=8bdf78b9:4cad434c:3a30392d:8463c7e0 sync_speed_max=1000000
after I makes changes to the file I rebuild the initramfs image file and
reboot. The thing that seems strange to me is that the other item I set
(sync_speed_max) is changed accordingly, only "group_thread_cnt" fails
to set (it's always =0).
Why "sync_speed_max" is set while "group_thread_cnt" it is not? Any clue?
Thanks in advance, kind regards.
--
Franco Martelli
^ permalink raw reply [flat|nested] 5+ messages in threadend of thread, other threads:[~2025-10-21 0:33 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-10-17 14:07 Unable to set group_thread_cnt using mdadm.conf Franco Martelli 2025-10-20 14:40 ` Xiao Ni 2025-10-20 19:22 ` Franco Martelli 2025-10-21 0:33 ` Xiao Ni -- strict thread matches above, loose matches on Subject: below -- 2025-10-14 19:53 Franco Martelli
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