[200] C200 and software raid

[xray]

Hello Guys,

I'm planning to get a second hdisk into my C200. I would like to keep my data safer as i have almost 1.5TB on it already and i do not want to loose in case of a hdd crash/damage. Therefore i would like to setup a RAID1 mirror on the C200.

Can somebody tell me if the support for raid1 is built into the factory default kernel?
I have cross-compiled mdadm and trying to create a raid1 array but i'm getting the following message:

Code:

C200[share]# ./mdadm --create /dev/md0 --level=raid1 --raid-devices=1 /dev/sda3 --force
mdadm: /dev/sda3 appears to contain an ext2fs file system
    size=1953504K  mtime=Sun Nov 20 11:23:14 2011
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
Continue creating array? yes
mdadm: unexpected failure opening /dev/md0

C200[share]# ls -l /dev/md0
brw-------    1 root     root       9,   0 Dec  1 18:25 /dev/md0

I have compiled some dm-mod.ko md.ko kernel modules but it fails to load as it is saying in the dmesg like this:

Quote:raid1: exports duplicate symbol dm_unregister_target (owned by kernel)
raid1: exports duplicate symbol dm_register_target (owned by kernel)
raid1: exports duplicate symbol dm_io (owned by kernel)
raid1: exports duplicate symbol dm_io_client_destroy (owned by kernel)
raid1: exports duplicate symbol dm_io_client_resize (owned by kernel)

For me it looks like that the RAID support is built in to the kernel. But why mdadm can not handle it then? Maybe partial support is only built in?

[Willem53]

question is... will it still be a functional mediaplayer if you get the software raid working?
The bus disk and network I/O has always been minimal with a little capacity over the BluRay I/O speed.
Would you want to split this limited capacity over two disk and if you succeed can it still play back a BluRay ISO.
Why raid? you put content on a disk and it sits there static until at some point you decide to delete it.
Raid is good to keep you data safe in a dynamic disk usage.

I would say just run a backup to a USB disk in the time your not watching.
Sort of after you finished watching select "run incremental backup" to destination:.....

[xray]

finally i managed to work raid1 on my nmt c200 At the moment still with one disk (degraded array), but i will do some tests to examine the speed as soon as i will buy/get my second 1.5T harddisk

Code:

C200[~]# lsmod |grep raid1
raid1 34816 1 - Live 0xc02a8000
md_mod 106176 1 raid1, Live 0xc02c0000

Code:

sh-3.00# ./mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda3 missing
mdadm: /dev/sda3 appears to contain an ext2fs file system
    size=1953504K  mtime=Fri Dec 30 11:05:07 2011
mdadm: /dev/sda3 appears to be part of a raid array:
    level=raid1 devices=2 ctime=Fri Dec 30 11:18:56 2011
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

Code:

C200[~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda3[0]
      1952468 blocks super 1.2 [2/1] [U_]

unused devices: <none>

Code:

C200[~]# /share/raid/mdadm/mdadm --detail /dev/md0
/dev/md0:
        Version : 1.2
  Creation Time : Fri Dec 30 11:18:56 2011
     Raid Level : raid1
     Array Size : 1952468 (1907.03 MiB 1999.33 MB)
  Used Dev Size : 1952468 (1907.03 MiB 1999.33 MB)
   Raid Devices : 2
  Total Devices : 1
    Persistence : Superblock is persistent

    Update Time : Fri Dec 30 11:19:20 2011
          State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
  Spare Devices : 0

           Name : C200:0  (local to host C200)
           UUID : 9dfdec93:ed7a62e6:4028ddb9:e90d7643
         Events : 2

    Number   Major   Minor   RaidDevice State
       0       8        3        0      active sync   /dev/sda3
       1       0        0        1      removed

[wye]

I'm happy to see this is possible, I'm looking forward to create a raid0 (stripping) on a C series myself. My goal is to maximize local throughput in order to minimize the time spent with PAR repairs and extracting/playing RAR archives. Storage size or error correction does not apply to my needs, since I don't keep movies after I see them.

BTW, anyone tried toying around with 2 fast SSDs in a strip raid on C series? I wonder what are the limitation of the SATA controller that popcorn uses. The reason why I'm asking is avoid buying too fast SSDs that would be over the limit of the controller and thus be wasted. E.g. on my PC the default ICH0R controller on the X58 mobo limits me to around 650 MBytes / sec (its a controller specific global limitation, not SATA 1/2/3 limit). Anyone knows the name of the SATA controller chip for C-200 or C-300?

Also, how does popcorn handle downloading from usenet in background while a movie is playing? It it working at all? If yes, does it throttle CPU and I/O priority on the usenet client to avoid interrupting playback?

Thanks.

---

Just a little update from the research I've done: it looks like the SATA support is embedded inside the Sigma SoC. According to http://www.sigmadesigns.com/uploads/docu...40_br.pdf, it says its SATA II, but only "1.5 Gbps" (probably per channel). That is a bit odd, since SATA 1 is 1.5 Gbps per channel, and SATA II is 3 Gbps per channel.

---

[wye]

Anyone with a SSD inside the popcorn hour is willing to do a "hdparm -t" to measure its local speed?

[xray]

Finally i got a second HDD and did some measurements.

Disk write speed to RAID1 md device:

Code:

C200[mnt]# /usr/local/bin/dd if=/dev/zero of=/tmp/mnt/700mb count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 66.7269 s, 11.0 MB/s
C200[mnt]# /usr/local/bin/dd if=/dev/zero of=/tmp/mnt/700mb count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 66.6854 s, 11.0 MB/s
C200[mnt]# /usr/local/bin/dd if=/dev/zero of=/tmp/mnt/700mb count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 66.4996 s, 11.0 MB/s

So as you can see the average disk write speed to RAID1 md device is 11MB/s.

Disk write speed to single SATA device:

Code:

C200[mnt]# /usr/local/bin/dd if=/dev/zero of=/share/700mb count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 62.2818 s, 11.8 MB/s
C200[mnt]# /usr/local/bin/dd if=/dev/zero of=/share/700mb count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 63.3755 s, 11.6 MB/s
C200[mnt]# /usr/local/bin/dd if=/dev/zero of=/share/700mb count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 61.6711 s, 11.9 MB/s

Average disk write speed to single SATA disk: 11,76 MB/s.

My conclusion is that there is no significant speed differencies between RAID1 and single disk but wirte to RAID1 is little bit slower.

---

Disk read test.

Read from single SATA disk:

Code:

C200[mnt]# /usr/local/bin/dd if=/share/700mb of=/dev/null count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 15.0909 s, 48.6 MB/s
C200[mnt]# /usr/local/bin/dd if=/share/700mb of=/dev/null count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 14.875 s, 49.3 MB/s
C200[mnt]# /usr/local/bin/dd if=/share/700mb of=/dev/null count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 15.1397 s, 48.5 MB/s

Avg.: 48,8 MB/s

Read from RAID1 md device:

Code:

C200[mnt]# /usr/local/bin/dd if=/tmp/mnt/700mb of=/dev/null count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 15.9983 s, 45.9 MB/s
C200[mnt]# /usr/local/bin/dd if=/tmp/mnt/700mb of=/dev/null count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 15.8117 s, 46.4 MB/s
C200[mnt]# /usr/local/bin/dd if=/tmp/mnt/700mb of=/dev/null count=1400k
1433600+0 records in
1433600+0 records out
734003200 bytes (734 MB) copied, 15.8919 s, 46.2 MB/s

Avg.: 46,16 MB/s

---

Both test performed with:

WD WD15EARS + SAMSUNG HM160HI (2G partition in SW RAID1)

[seba0902]

Anyone would help me of setting up this?I have 2 hdd's of 1tb and need to explain me how to do it? I want help in installing mdadm with telnet and about configuring is not a problem,just see mdadm up and runing.Thanks in advance

[seba0902]

I tried to install but no results,Im also newbie at this,get the folowing error:

Code:

sh-3.00# opkg update

sh-3.00# opkg install mdadm
Collected errors:
* opkg_install_cmd: Cannot install package mdadm.
.
Collected errors:
* deb_extract: /tmp/opkg-esRkOw/mdadm-0.7.1.tar.bz2: invalid magic
* pkg_init_from_file: Failed to extract control file from /tmp/opkg-esRkOw/mdadm-0.7.1.tar.bz2.

Any help please?

[seba0902]

I have ended up by starting installing mdadm.mips.ipk and when opkg says that missing dependency libc6 I download it and install and now I get the folowing error:

Code:

sh-3.00# opkg update
opkg: error while loading shared libraries: /usr/local/lib/libc.so.6: ELF file data encoding not little-endian

Any suggestions?Thanks in advance

[seba0902]

It seems like this forum is dead...I will post anyway.After I get this error I manage to reformat my harddrive and reinstall nmt apps and now i get the folowing error

Code:

sh-3.00# opkg install mdadm_3.1.4-r1_mips.ipk
Installing mdadm (3.1.4-r1) to root...
Collected errors:
* satisfy_dependencies_for: Cannot satisfy the following dependencies for mdadm:
*      libc6 (>= 2.12) *
* opkg_install_cmd: Cannot install package mdadm.
sh-3.00# opkg install libc6
Package libc6 (2.8-1) installed in root is up to date.

I have downloaded mdadm with wget and when I try to install give me this.
Any help would be apreciate,thanks in advance

[accident]

it's also a topic with not that many people interested in it. perhaps you can try to pm the people that originally made it, that would email them to check the forum

[seba0902]

Thank you,I will do that

[vaidyasr]

I'll give it a try soon, and it may take a while, as it involves kernel modules.

[seba0902]

Thank you, I will wait for it,It would be also nice to have it via OPKG.

[seba0902]

Also maybe xray would like to share how has he do it?