[mythtv-users] OT? Shuttle + ProRAID or Obsidian case for i3/i5 Myth BE ?

Martin Bene Martin.Bene at icomedias.com
Thu Sep 22 12:49:30 UTC 2011


>  What I am not telling you is that I want to use the same hardware setup as the Myth server for my NAS and Zoneminder servers.   And both of them DO need failsafe storage.
> The NAS server because it will be storing precious pictures, backups from laptops, business documents, etc.
> Zoneminder because we want to archive images from a dozen security cameras for 90 days or so.

> Given that I have some machines, though not necessarily the Myth server, that do need foolproof storage, what do you recommend ? 
>  rsync the various machines onto a different machine each during off hours ?

I would avoid the shuttle/raidbox combination: In a big case you get much better cooling, you can use bigger fans with a longer livetime and it's MUCH less hassle to replace parts if something breaks. Most external raidboxes I've tries so far are rather slow and often don't provide adequate cooling for the  drives. Also, you'll be much more limited in the way you configure your storage space.

Go with the big case, use the onboard SATA ports in AHCI mode and run Linux software raid. This gives you the flexibility to use a smaller part of your HDDs for failsafe storage and/or fast raid10 and a larger part for non-redundant myth storage groups. I've done something similar for my backend:

HDD: 6x 3TB, Mythbuntu 11.04, Asus P8H67-V Motherboard, i5-2500 CPU, Big case with 6 3.5" Bays and 2 extra case fans providing cooling for the drives.

The mainboard has no problem booting off the 3 TB drives, so no need for an extra boot device. Drives obviously have to be partitioned in gpt mode.

Partitions (same on all drives):
#	size	name		comment
-------- --------- ------------------ ----------------------------------------------------
1	8M	bios_grub	needed for grub on gpt partitioned drives
2	1G	boot		Used for /boot 6-way Raid1 mirror
3	10G	root		Used for / Raid10
4	50G	nas		Used for Raid5 file shares / NAS
5	2941G	video		Plain partition for use in storage groups

Device		size	level	partitions	comment
------------------ -------- ---------- ------------------ ------------
/dev/md0:	1G 	raid1	sd[a-f]2	Raid1 with 6 drives for /boot partition. Booting off raid1 is supported by grub and 
						this makes sure that valid boot config is available on all drives, so no matter which 
						drive fails or how you swap drives around the system will still be able to boot.

/dev/md1:	30G 	raid10	sd[a-f]3 	Raid 10 for fast / filesystem including mysql DB and swap space. 

/dev/md2:	250G 	raid5	sd[a-f]4	Raid5 for redundant file shares 

		2940G	no raid	sd[a-f]5:	Plain partitions for use in storage groups for mythtv

Personaly I like the added flexibility and possibility of using snapshots that LVM can provide, so I've added LVM to the mix. I've created separate Volume Groups for the different Raid levels to make setup easier. The logical volumes leave some free space in each volume group so sufficient space for snapshots is available.

Volume Groups:
/dev/md1	RootVG
/dev/md2	NasVG

Logical Volumes:
/dev/RootVG/swap	2GB
/dev/RootVG/root	20GB
/dev/NasVG/nas	240GB

File system is ext4 for all file systems; possibly other file systems could provide better performance but this is easiest from a setup and maintenance POV.

/boot				/dev/md0
/				/dev/RootVG/root
/usr/nas			/dev/NasVG/nas
/var/lib/mythtv/recordings1	/dev/sda5
/var/lib/mythtv/recordings2	/dev/sdb5
/var/lib/mythtv/recordings3	/dev/sdc5
/var/lib/mythtv/recordings4	/dev/sdd5
/var/lib/mythtv/recordings5	/dev/sde5
/var/lib/mythtv/recordings6	/dev/sdf5

Hope this gives you some ideas on how you could configure your new backend.

Bye, Martin
No Disclaimer.icomedias

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