Arch Linux

yezhengmao

Member

Registered: 2023-02-16

Posts: 2

RAID5 status change between clean and active regularly ?

I`m creat a raid5 array, and if I do not mount it, the disk io speed is 0.
But when I mounted it, there are some io to write and read, but in fact, I didn't make any io requests except mount it.
Using mdadm to check it, I saw the state is changed between "clean" and "active" frequently.
Does it work fine? Why there are some write transactions?

/dev/md0:
           Version : 1.2
     Creation Time : Tue Feb 14 14:56:29 2023
        Raid Level : raid5
        Array Size : 11720653824 (10.92 TiB 12.00 TB)
     Used Dev Size : 3906884608 (3.64 TiB 4.00 TB)
      Raid Devices : 4
     Total Devices : 4
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Thu Feb 16 13:55:06 2023
             State : clean
    Active Devices : 4
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 0

            Layout : left-symmetric
        Chunk Size : 256K

Consistency Policy : bitmap

xxx

    Number   Major   Minor   RaidDevice State
       0       8       33        0      active sync   /dev/sdc1
       1       8       49        1      active sync   /dev/sdd1
       2       8        1        2      active sync   /dev/sda1
       4       8       17        3      active sync   /dev/sdb1

-------------------------------------------------------------
/dev/md0:
           Version : 1.2
     Creation Time : Tue Feb 14 14:56:29 2023
        Raid Level : raid5
        Array Size : 11720653824 (10.92 TiB 12.00 TB)
     Used Dev Size : 3906884608 (3.64 TiB 4.00 TB)
      Raid Devices : 4
     Total Devices : 4
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Thu Feb 16 14:07:04 2023
             State : active
    Active Devices : 4
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 0

            Layout : left-symmetric
        Chunk Size : 256K

Consistency Policy : bitmap

xxx

    Number   Major   Minor   RaidDevice State
       0       8       33        0      active sync   /dev/sdc1
       1       8       49        1      active sync   /dev/sdd1
       2       8        1        2      active sync   /dev/sda1
       4       8       17        3      active sync   /dev/sdb1

------------------------------------------------

Ferdinand

Member

From: Norway

Registered: 2020-01-02

Posts: 338

Re: RAID5 status change between clean and active regularly ?

Your RAID looks good to me.

If the RAID isn't otherwize used, I'd say sporadic accessing is probably just householding; you've built a software RAID with mdadm, so I'll imagine mdadm is checking in on it from time to time, and also Linux is keeping an eye on it's filesystems - but in order to check what's going on more properly, iotop is a good tool.

Also, output, like your mdadm --detail you shared, is much more readable if you enclose it in [⁣code] [⁣/code] tags.

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yezhengmao

Member

Registered: 2023-02-16

Posts: 2

Re: RAID5 status change between clean and active regularly ?

Your RAID looks good to me.

If the RAID isn't otherwize used, I'd say sporadic accessing is probably just householding; you've built a software RAID with mdadm, so I'll imagine mdadm is checking in on it from time to time, and also Linux is keeping an eye on it's filesystems - but in order to check what's going on more properly, iotop is a good tool.

Also, output, like your mdadm --detail you shared, is much more readable if you enclose it in [⁣code] [⁣/code] tags.

I try the iotop, but there is no process to write the disk. But using fuser to trace It, only the kernel thread accesses it.