Raid 0 software raid issues (?)

[xabbu]

@Slyfer1

/dev/md0echo

typo? the echo behind md0 looks wrong.

[Slyfer1]

It is wrong haha, sorry, just a copy/paste error.

LC_ALL=C sudo mdadm --action=check /dev/md0                                                 
mdadm: Count not set action for /dev/md0 to check: No such file or directory

[Nachlese]

@Slyfer1

mdadm: Count not set action for /dev/md0 to check: No such file or directory

I’m just wondering here:
this does not look like copy/paste -

… Count not set action …

?
that’s not english, that is a typo

[Slyfer1]

@Nachlese

… Count not set action …

Yeah true. It prints it differently, but the error is the same: ... No such file or directory

[Nachlese]

But why would you not copy/paste but type it instead and introduce errors and uncertainty that way?

It was a rhetorical question and I don’t want to derail the thread - sorry.
No response wanted or needed.

[linux-aarhus]

@linux-aarhus

But since the scrubbing is to locate disk errors and repair data before failure - raid0 is just speed - no redundancy - is it necessary in such case?

Now I know why - it is indeed related to the fact that it is raid0 - there is no such action for that kind of raid.

If you list the sys content for your raid you will see the sync_action file does not exist

ls /sys/block/md0/md

Example from my test box

[server1 ~]# cat /proc/mdstat
Personalities : [raid10] [raid0] 
md126 : active raid0 sdc1[1] sdb1[0]
      838596608 blocks super 1.2 512k chunks
      
md127 : active raid10 sde1[1] sdd1[0]
      419298304 blocks super 1.2 512K chunks 2 far-copies [2/2] [UU]
      [=======>.............]  resync = 36.6% (153630848/419298304) finish=23.4min speed=188474K/sec
      bitmap: 3/4 pages [12KB], 65536KB chunk

sample raid0

[server1 ~]# ls /sys/block/md126/md
array_size          dev-sdb1         metadata_version   reshape_position
array_state         dev-sdc1         new_dev            resync_start
bitmap              fail_last_dev    raid_disks         safe_mode_delay
chunk_size          layout           rd0                serialize_policy
component_size      level            rd1                uuid
consistency_policy  max_read_errors  reshape_direction

as opposed to raid10far2

[server1 ~]# ls /sys/block/md127/md
array_size          dev-sdd1          mismatch_cnt       safe_mode_delay      sync_min
array_state         dev-sde1          new_dev            serialize_policy     sync_speed
bitmap              fail_last_dev     raid_disks         suspend_hi           sync_speed_max
bitmap_set_bits     last_sync_action  rd0                suspend_lo           sync_speed_min
chunk_size          layout            rd1                sync_action          uuid
component_size      level             reshape_direction  sync_completed
consistency_policy  max_read_errors   reshape_position   sync_force_parallel
degraded            metadata_version  resync_start       sync_max

[Slyfer1]

Awww goddamn!

If I’d only known this earlier Would’ve saved me a lot of brain juice

Thank you so much for finally solving this and all of your efforts! Case closed!