How to set: stripe_cache_size

gjc33 · Nov 26th 2025

I have a RAID 5 setup and want to increase the stripe_cache_size. Reading through various posts on the forum, they suggest:

Code

echo 16384 > /sys/block/md0/md/stripe_cache_size

However, I don't have any md folders under /sys/blocks and cant find stripe_cache_size, under any of the subfolders there in (loop0 - loop4 and sda - sde)

Am I supposed to create the md0 folder structure or change it some other way?

ryecoaaron · Nov 26th 2025

Quote from gjc33

Am I supposed to create the md0 folder structure or change it some other way?

No. What is the output of cat /proc/mdstat

Quote from gjc33

/sys/blocks

There is no 's' on block

gjc33 · Nov 26th 2025

root@backupserver:/sys# cat /proc/mdstat

Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]

unused devices: <none>

Yes /sys/block (sorry typo )

ryecoaaron · Nov 26th 2025

You have no raid array assembled. That is why you don't see anything in /sys/block.

gjc33 · Nov 26th 2025

??? I have a fully operational RAID 5 with mergerfs / SMB share and ~15TB of data.

Code

root@mediaserver:/# cat /etc/snapraid/JBOD.conf

# This file is auto-generated by openmediavault (https://www.openmediavault.org)
# WARNING: Do not edit this file, your changes will get lost.

autosave 0



# drives
#####################################################################
# OMV-Name: BAY1-P  Drive Label:
parity /srv/dev-disk-by-uuid-87d1a554-4a3e-439f-ace3-3d748190b26a/snapraid.parity

#####################################################################
# OMV-Name: BAY2  Drive Label:
content /srv/dev-disk-by-uuid-165491a1-9172-47de-872e-716f755de0d9/snapraid.content
data BAY2 /srv/dev-disk-by-uuid-165491a1-9172-47de-872e-716f755de0d9

#####################################################################
# OMV-Name: BAY3  Drive Label:
content /srv/dev-disk-by-uuid-8c29eccb-c0aa-4712-862d-d1d045e427cb/snapraid.content
data BAY3 /srv/dev-disk-by-uuid-8c29eccb-c0aa-4712-862d-d1d045e427cb

#####################################################################
# OMV-Name: BAY4  Drive Label:
content /srv/dev-disk-by-uuid-08f4272e-fac5-4523-af5b-c65065ec656a/snapraid.content
data BAY4 /srv/dev-disk-by-uuid-08f4272e-fac5-4523-af5b-c65065ec656a



exclude *.unrecoverable
exclude lost+found/
exclude aquota.user
exclude aquota.group
exclude /tmp/
exclude .content
exclude *.bak
exclude /snapraid.conf*

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ryecoaaron · Nov 26th 2025

Quote from gjc33

I have a fully operational RAID 5 with mergerfs / SMB share and ~15TB of data.

snapraid isn't real raid. You can't set cache size for snapraid. You would need mdadm or zfs or btrfs raid to do that.

gjc33 · Nov 26th 2025

Quote from ryecoaaron

... You can't set cache size for snapraid.

Ah OK.

Does that mean that none of these tips will help either:
RAID Rebuild Speed Tips

ryecoaaron · Nov 26th 2025

Quote from gjc33

Does that mean that none of these tips will help either:

correct. snapraid can't rebuild. it can sync. I recommend reading the snapraid manual. it is very good. https://www.snapraid.it/manual

How to set: stripe_cache_size

ryecoaaron Nov 26th 2025

Participate now!

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