mirroring partitions?

[evanesce69]

Is it possible to mirror a SLOG using identical but different partitions on the same SSD? Say, create two 2G partitions then mirror the two and set that "volume" as SLOG?

Would it face the same risk as a single drive failing since the mirror exists on a single SSD?
Would the SATA interface be restricted according to bandwidth accessing the two partitions?

Most importantly, is this idea realistic, ill advised or just plain old "dupid"?

Opinions welcome!

Thank you for any help!

 

[cyberjock]

Is it possible to mirror a SLOG using identical but different partitions on the same SSD? Say, create two 2G partitions then mirror the two and set that "volume" as SLOG?

Would it face the same risk as a single drive failing since the mirror exists on a single SSD?
Would the SATA interface be restricted according to bandwidth accessing the two partitions?

Most importantly, is this idea realistic, ill advised or just plain old "dupid"?

Opinions welcome!

Thank you for any help!

This is plain old "dupid" for every reason you just mentioned.

If you want SLOG mirrors you need 2 physical SSDs. Even better if you can throw them on different SATA controllers IMO.

In fact, its "dupid" to put the SLOG and L2ARC on the same physical SSD too. It just makes both suck at their jobs.

 

[evanesce69]

Thanks cyberjock... What about on a 320g fusionIO?

I'm a research chemist so it's my job to come up with "dupid" ideas... but you never know if you don't try/ask.

 

[cyberjock]

Those are single drive still. The whole reason for mirroring is so you have 2 copies on 2 different physical disks. You could buy 2 FusionIO drives, but my gosh is that expensive!

 

[Rocky]

Mirroring doesn't buy anything on a single drive - you lose that drive both "sides" of the mirror is gone - there's no speed benefit as system has to go to the same place to get the data regardless of which side of the "mirror" it's on. In short - there's no speed benefit (may even be worse) and there isn't any redundancy benefit... it's a lose/lose situation.

 

[evanesce69]

Thanks guys.

For work I'd spring for the second fusionIO, but for home media... I think I'll just get a pair of the 8G Transcend (TS8GSSD500) SLC drives.

What do you think about the 8G PATA modules that plug directly onto the motherboard?

Thoughts?

 

[cyberjock]

Don't go cheap. The slog fails at an inopportune time and your pool could have a VERY bad day. Go with something reliable.

 

[evanesce69]

Regarding the SATA drives, they looked decent... is there something I should know?
Regarding the PATA drives, they were a curiosity... they only had 50-70 MB/sec transfer rates write/read. I know that wouldn't work for slog, but maybe for the OS?

backstory: I'm playing with old hardware ATM to get a feel for freeNAS.

MSI 790FX-gd70
4G ddr3 1066
Phenom II 840
3.2G Quantum Fireball PATA - OS
3x WD 1G + 1x hitachi 1G - storage pool
dual realtek NIC - onboard

 

[cyberjock]

Just use a USB stick for the boot device and be done with it. You don't need to reinvent the wheel.

 

[evanesce69]

LOL... I've heard that many, MANY times before... on many different subjects...

Ok, well, I believe I have enough information to start buying for discs and disc subsystems.
Now I going to look for ways to bridge Ethernet ports (aggregation).

Again, thanks to everyone who contributed here!