RAID F1 and SHR may coexist

[pengkui]

After setting support_syno_hybrid_raid to "yes" and supportraidgroup to "no", it appears that RAID F1, SHR-1 and SHR-2 can coexist. One can choose RAID F1 on SSD drives and SHR-1/2 on HDD drives on the same machine.

This seems to run against your README statement "Changing to RAID F1 disables SHR, and changing to SHR disables RAID F1." Is there a reason to impose this mutual exclusiveness?

[007revad]

Thanks. And thank you for including screenshots.

This seems to run against your README statement "Changing to RAID F1 disables SHR, and changing to SHR disables RAID F1." Is there a reason to impose this mutual exclusiveness?

From what I read on the Xpenology forum I thought they said that in DSM you could have RAID F1 or SHR but not both. I've never had 3 SATA SSDs to test it with.

Now I'm wondering if my script is just disabling and enabling SHR - and RAID-F1 is always enabled (on models that support RAID F1). Which raises the question of how to enable RAID F1 on other models.

[pengkui]

https://xpenology.com/forum/topic/9394-installation-faq/?tab=comments#comment-131458

This xpenology post suggests that

"The Synology models that support RAIDF1 are the same as those that do not officially support SHR. This includes the XPEnology-enabled DS3615xs+ and DS3617xs+ platforms. Note that SHR can be enabled on these platforms by modifying /etc.defaults/synoinfo.conf, with no impact to RAIDF1 functionality."

"The MDRAID modifications that enable RAIDF1 are compiled into the DSM kernel. The consumer-oriented DSM platforms do not contain those changes, including the XPEnology-enabled DS916+ and DS918+ platforms. Creation and maintenance of a RAIDF1 is not possible on those systems."

[007revad]

"The MDRAID modifications that enable RAIDF1 are compiled into the DSM kernel. The consumer-oriented DSM platforms do not contain those changes,"

That makes sense.

Before I saw your last comment I found some incorrect information here https://www.reddit.com/r/synology/comments/jueg8z/comment/gcbv9wp/ that said "RAIDF1 is an option compiled into their customized version of mdm, and therefore there is no way create a RAIDF1 on unsupported device."

After checking 112 different model's mdadm I found that all models include raidf1 in mdadm (even single drive Synology NAS!) so I knew that was wrong.

So my raidf1_shr_switch script needs an update to make it just shr_switch

[pengkui]

How are you planning to change the script? 😄

I noticed https://kb.synology.com/en-us/DSM/tutorial/What_is_RAID_Group

DSM 7.0 and above

On models with support for RAID groups
- RAID F1

On models without support for RAID groups
- RAID F1, SHR

If "models with support for RAID groups" can be signified by supportraidgroup="no",

is it fair to assume the following outcomes?

• supportraidgroup="no" & support_syno_hybrid_raid="yes": both F1 and SHR are available
• supportraidgroup="yes" & support_syno_hybrid_raid="no": only F1 is available
• supportraidgroup="yes" & support_syno_hybrid_raid="yes": only F1 is available

[pengkui]

This KB article https://kb.synology.com/en-us/DSM/tutorial/What_is_RAID_Group especially the row "On models without support for RAID groups" where F1 and SHR are mentioned together seems to suggest that the mutual exclusivity is between RAID group and SHR, not between F1 and SHR.

[007revad]

seems to suggest that the mutual exclusivity is between RAID group and SHR, not between F1 and SHR.

It does seem to suggest that.

How are you planning to change the script? 😄

I was going to remove all reference to RAID F1 and change it to either disable or enable SHR. But having read that page you linked I think I'll just change the RAID F1 text to RAID Group. So it will actually be Synology_RAID-Group_SHR_switch

I noticed https://kb.synology.com/en-us/DSM/tutorial/What_is_RAID_Group

DSM 7.0 and above

On models with support for RAID groups
- RAID F1

On models without support for RAID groups
- RAID F1, SHR

If "models with support for RAID groups" can be signified by supportraidgroup="no",

is it fair to assume the following outcomes?

• supportraidgroup="no" & support_syno_hybrid_raid="yes": both F1 and SHR are available
• supportraidgroup="yes" & support_syno_hybrid_raid="no": only F1 is available
• supportraidgroup="yes" & support_syno_hybrid_raid="yes": only F1 is available

• The only "model" that has supportraidgroup="no" is VirtualDSM.
• The models that support RAID groups all have supportraidgroup="yes"
• The models that don't support RAID groups don't have any supportraidgroup setting in synoinfo.conf

It definitely looks like:

• You can have RAID Groups or SHR but not both.
• RAID F1 is always available (on models that support RAID F1).

I would take your scenario one step further to say:

• supportraidgroup="no" & support_syno_hybrid_raid="yes": both F1 and SHR are available, but not RAID groups
• supportraidgroup="yes" & support_syno_hybrid_raid="no": both F1 and RAID groups are available, but not SHR
• supportraidgroup="yes" & support_syno_hybrid_raid="yes": both F1 and RAID groups are available, but not SHR

The one exception to this is the HD6500 which officially does not support SHR or RAID F1. It has supportraidgroup="yes" but does not have support_syno_hybrid_raid.

[pengkui]

FYI, my current setup is as follows:

DS3617xs, DSM 7.2, and /etc.defaults/synoinfo.conf has

supportraidgroup="no"
support_syno_hybrid_raid="yes"

Screenshot of Storage Manager: