SSD overprovisioning

[ybcnyc]

Hi

I have 6 x 1TB (930GB) that i plan on testing in 3x2 mirror and did overprovision them in windows but in FreeNAS it shows as 1TB, doesn't really take into consideration the space that was set aside (120GB), leaving the usable space at 810GB. Is this just a GUI glitch ?

 

[ybcnyc]

actually one each of the TB drives shows

> 63 1953525105 da4 MBR (931G)
63 1985 - free - (992k)
2048 273491968 1 fat16 (130G)
273494016 1680031152 - free - (801G)

so can i leave the OP partition alone or do i need to do something to it (fat16 130GB) partition

actually when I did mirror on two 60GB ssd which where OP in windows after creating the mirror the pool takes all space on the drive

34 117231341 da0 GPT (55G)
34 1024 1 bios-boot (512k)
1058 6 - free - (3.0k)
1064 117230304 2 freebsd-zfs (55G)
117231368 7 - free - (3.5k)

=> 34 117231341 da1 GPT (55G)
34 1024 1 bios-boot (512k)
1058 6 - free - (3.0k)
1064 117230304 2 freebsd-zfs (55G)
117231368 7 - free - (3.5k)

how can i properly OP in freenas ? Thanks

 

[Robert Trevellyan]

Whatever partitioning you did in Windows is overwritten when you use a drive in FreeNAS.

how can i properly OP in freenas ?

The only way that springs to mind would be to use the CLI to create the pool from partitions. At that point, you'd be better off not using FreeNAS.

 

[depasseg]

You can use camcontrol commands to limit the size of the drive. I've done this for my SLOG.

Sent from my Nexus 9 using Tapatalk

 

[ybcnyc]

thanks guys. looks like camcontrol is the way to go. is this permanent and survives system reboots ? also do i need to do secure erase of the drives prior since it looks like they already have partitions on them.

 

[depasseg]

Yes and yes. I didn't SE and I had partitions and it worked fine.
https://forums.freenas.org/index.php?threads/how-to-resize-slog-ssd.40071/#post-250692

 

[Robert Trevellyan]

It has also occurred to me that you could set a large value for the swap size on the System | Advanced tab. Since swap should be barely used on a well-designed FreeNAS, this would have almost the same effect as over-provisioning, and you wouldn't have to resort to the GUI.

 

[ybcnyc]

i did the camcontrol but set the wrong value. is there a way to redo it. when i assign the camcontrol again it says it was already done
camcontrol: Max address has already been set since last power-on or hardware reset
any ideas ?
camcontrol man says
-s max_sectors

Configures the maximum user accessible sectors of the
device. This will change the number of sectors the device
reports.

WARNING! WARNING! WARNING!

Changing the max sectors of a device using this option will
make the data on the device beyond the specified value
inaccessible.

Only one successful -s max_sectors call can be made without
a power-on reset or a hardware reset of the device.

can i revert to factory to set it again ?

 

[depasseg]

Only one successful -s max_sectors call can be made without
a power-on reset or a hardware reset of the device.

Just shutdown, poweroff, and power on

 

[ybcnyc]

ok i did that and able to set the HPA size again. however one drive won't take it. it just never changes the value ?

 

[ybcnyc]

very stragne, all drives were able to change the value except one

EDIT: after few tries it did take the command successfully.

 

[ybcnyc]

also to create three way mirror how can i select which member belongs to each mirror? (manual doesn't have 3 mirror option). also selection tool picks drives in order vs how i want them to be arranged) so i guess cli is the only option ? zpool create MYSTOR mirror da0 da3 da6 mirror da1 da4 da7 mirror da2 da5 da8.

EDIT: created 3 way mirror in CLI, didn't see it in GUI so exported in CLI and imported from GUI solved it