Alt-F com Raid5

[Nasp]

Olá João Cardoso

Deixa-me agradecer-te primeiro pela excelente firmware alternativa que
vens desenvolvendo no ultimo ano para a DNS-323, muito útil e com
imensas funcionalidades que a firmware original não têm! Depois peço
desculpa por não escrever em Inglês, mas o meu Inglês "escrito" não é
dos melhores...

Uso a Alt-F na minha ch3snas, experimentei a versão reloaded, mas
depois logo fiz o flash. Já tenho a ch3snas a mais de dois anos
(recentemente até comprei uma dns-320) e ao longo destes dois anos
tenho usado bastante a ch3snas, mesmo como maquina de backups (time
machine) e downloads (nzbget e transmission) tudo via ffp do fonz.

Ando interessando em experimentar um Raid5 em três discos e é neste
sistema que tenho algumas duvidas de novato :)

1 - Posso utilizar 3 discos da mesma capacidade, mas um deles de
diferente marca ?
2 - Os dados são dividos pelos três discos com a paridade isso
percebo, mas então sempre que quero aceder a um ficheiro estou a usar
os 3 discos ? Isto tudo por causa da poupança de energia, porque
parece-me que em raid 5 tenho sempre todos os discos ligados sempre
que acedo a algum ficheiro. Correcto ?

3 - A ultima pergunta, mesmo com este raid5 posso a mesma ligar uma
penusb ou outro disco rígido por usb e instalar ai o ffp, ou o
debian ? Isto de modo a não interferir com os spindowns dos discos em
raid5. Ou terei que efectuar a instalação dentro do armazanamento em
raid5 ?


Mais uma vez obrigado... e se quiseres podes responder em Inglês,
também no sentido de ajudar alguém com às mesmas duvidas que eu, e que
obviamente não saiba Português.

[Joao Cardoso]

On Friday, April 22, 2011, Nasp <nasp...@gmail.com> wrote:
> Olá João Cardoso
>
> Deixa-me agradecer-te primeiro pela excelente firmware alternativa que
> vens desenvolvendo no ultimo ano para a DNS-323, muito útil e com
> imensas funcionalidades que a firmware original não têm! Depois peço
> desculpa por não escrever em Inglês, mas o meu Inglês "escrito" não é
> dos melhores...
>
> Uso a Alt-F na minha ch3snas, experimentei a versão reloaded, mas
> depois logo fiz o flash. Já tenho a ch3snas a mais de dois anos
> (recentemente até comprei uma dns-320) e ao longo destes dois anos
> tenho usado bastante a ch3snas, mesmo como maquina de backups (time
> machine) e downloads (nzbget e transmission) tudo via ffp do fonz.
>
> Ando interessando em experimentar um Raid5 em três discos e é neste
> sistema que tenho algumas duvidas de novato :)
>
> 1 - Posso utilizar 3 discos da mesma capacidade, mas um deles de
> diferente marca ?

For raid 5 all three disks can be of differente capacity. The capacity
of the smaller disk will dictate the raid5 size. All raid component
(partition) must be of equal size, that is the requirement.
The remaining space of each of the other disks will be used as a
normal linux filesystem, when using the Wizard.

> 2 - Os dados são dividos pelos três discos com a paridade isso
> percebo, mas então sempre que quero aceder a um ficheiro estou a usar
> os 3 discos ? Isto tudo por causa da poupança de energia, porque
> parece-me que em raid 5 tenho sempre todos os discos ligados sempre
> que acedo a algum ficheiro. Correcto ?

Yes, when using raid5 all three disks will be used, so all will be
wakeup when reading or writing.

> 3 - A ultima pergunta, mesmo com este raid5 posso a mesma ligar uma
> penusb ou outro disco rígido por usb e instalar ai o ffp, ou o
> debian ?

Yes, you can use a usb hub and use a also a usb pen.
But the limited usb bandwidth will be shared.
I would recommend using that setup only occasionaly.

> Isto de modo a não interferir com os spindowns dos discos em
> raid5. Ou terei que efectuar a instalação dentro do armazanamento em
> raid5 ?

I would use the remaining space in one of the disks (bigger than the
others) to install debian or ffp.
But will not ffp or debian use the data stored/to store in the raid5?
Then all disks would awake, no advantage in installing ffp/debian in a
usb pen or spare disk partition...

>
>
> Mais uma vez obrigado... e se quiseres podes responder em Inglês

So I did. Hope they can understand the question from the answer. I tried :)

Abraço.

> também no sentido de ajudar alguém com às mesmas duvidas que eu, e que
> obviamente não saiba Português.
>

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>

[Nasp]

Thanks Jcard, i understand very well...

but i must think what to do.... the 3 disks awake up it is an handicap
for power saving...

Maybe the best opcion is to put the ffp in a usbstick it torrents and
nzbs watch folders, but saving the files in a remaining space from the
bigger disk. It this, only the bigger disks awake up, correct ?

Two disks it 1.5tbytes and the third it 2tb, all in raid5. (3GB for
data + 1.5gb for recover (paring) ) and 500GB remaning, correct ? And
it is better to put the bigger disk inside the ch3snas.


abraço tuga :)



On 23 Abr, 02:04, Joao Cardoso <whoami.jc...@gmail.com> wrote:

[Joao Cardoso]

On Apr 23, 10:25 pm, Nasp <nasp2...@gmail.com> wrote:
> Thanks Jcard, i understand very well...
>
> but i must think what to do.... the 3 disks awake up it is an handicap
> for power saving...
>
> Maybe the best opcion is to put the ffp in a usbstick it torrents and
> nzbs watch folders, but saving the files in a remaining space from the
> bigger disk. It this, only the bigger disks awake up, correct ?

If no activity at all occurs at the raid5, yes, its disks will not be
wakeup.
If you want be sure that the disks in the raid will not be wakeup,
stop the raid or unmount the filesystem residing on it.

It is difficult to say what will happens without knowing what apps we
are talking about and what its configuration is.

> Two disks it 1.5tbytes and the third it 2tb, all in raid5. (3GB for
> data + 1.5gb for recover (paring) ) and 500GB remaning, correct ?

Right.

Don't forget to create swap partitions/"filesystems" on the disks. All
of them. 500MB is the value that dlink uses, and I think that's OK.
The Disk Wizard does it for you.

> And it is better to put the bigger disk inside the ch3snas.

Yes, I think so, but I see no strong reason to do it.

Be warned that I was not able to control disk spindow when using
external usb disks, so its better to make sure that the usb disk does
the spindown by itself.
Alt-F deals with all disks in the same way, be them internal or
external; the problem is that some/most of the usb to disk adapter
(chip) inside the usb enclosure might not handle spindown commands.

[Nasp]

The reason for put the bigger disk inside ch3snas, is because the
partition it the remain space that i use for downloads. It that i
don't use usb bandwitch, necessary if i acess on raid5 from other
computer...

thanks jcard!

[Nasp]

jcard, one more question...

And instead of a damaged disc, is the CH3SNAS that was damaged ?

Can i recover my precious files from the 3 disks in raid5 setup ? From
other computer ?


Sorry for one more newbie question, but it is very important to me.

tks.

[Joao Cardoso]

On May 1, 3:56 pm, Nasp <nasp2...@gmail.com> wrote:
> jcard, one more question...
>
> And instead of a damaged disc, is the CH3SNAS that was damaged ?
>
> Can i recover my precious files from the 3 disks in raid5 setup ? From
> other computer ?

Yes, if it has linux installed.

The same is true for the vendor's firmware, if the filesystem in use
is ext3 or raid is being used.

[Nasp]

It is normal to start a raid5 it an degraded state / rebuilding
automatically the green letters/disk ?

From the web interface i started a raid5 setup in the wizard mode. Two
times it ext3 and two times started it one disk in spare (sdc2,
usbdisk)




# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdc2[3] sda2[1] sdb2[0]
3905975296 blocks level 5, 512k chunk, algorithm 2 [3/2] [UU_]
[>....................] recovery = 2.0% (40129648/1952987648)
finish=2125.4min speed=14999K/sec
bitmap: 15/15 pages [60KB], 65536KB chunk

unused devices: <none>
# mdadm --detail /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Wed May 4 19:52:16 2011
Raid Level : raid5
Array Size : 3905975296 (3725.03 GiB 3999.72 GB)
Used Dev Size : 1952987648 (1862.51 GiB 1999.86 GB)
Raid Devices : 3
Total Devices : 3
Preferred Minor : 0
Persistence : Superblock is persistent

Intent Bitmap : Internal

Update Time : Wed May 4 22:10:27 2011
State : active, degraded, recovering
Active Devices : 2
Working Devices : 3
Failed Devices : 0
Spare Devices : 1

Layout : left-symmetric
Chunk Size : 512K

Rebuild Status : 2% complete

UUID : 3035c84d:53c602d8:f14276d4:8c7b141c (local to host
CH3SNAS)
Events : 0.1761

Number Major Minor RaidDevice State
0 8 18 0 active sync /dev/sdb2
1 8 2 1 active sync /dev/sda2
3 8 34 2 spare rebuilding /dev/sdc2
#

[Joao Cardoso]

On May 4, 10:13 pm, Nasp <nasp2...@gmail.com> wrote:
> It is normal to start a raid5 it an degraded state / rebuilding
> automatically the green letters/disk ?
>
> From the web interface i started a raid5 setup in the wizard mode. Two
> times it ext3 and two times started it one disk in spare (sdc2,
> usbdisk)

I'm not sure that I understand you said.

RAID5 is *created* in degraded mode with two drives, as, according to
the author, it is faster this way; then a rebuild phase with the third
drive starts, and at the end of the rebuilding the RAID must enter the
OK state.

*After* the creation and rebuilding, if the RAID is stopped and
restarted, or if the box is rebooted, it should *not* start in a
degraded state.

So, what is exactly your situation? Initial creation or starting/
rebooting after the initial creation/rebuilding finish?

[Nasp]

Ohhh... Ok

In this moment, 50% of the rebuild state is done...


I have started the raid5 in degraded state, like you tell it is
normal.

tks jcard.

[Nasp]

Initial creation is my situation....

Now more than 16hours of creation the rebuilding state is at 50%....

[Joao Cardoso]

On May 5, 2:27 pm, Nasp <nasp2...@gmail.com> wrote:
> Ohhh... Ok
>
> In this moment, 50% of the rebuild state is done...

According to the data you posted:

finish=2125.4min speed=14999K/sec

this gives about 2125/60= 35 hours to accomplish.

> I have started the raid5 in degraded state, like you tell it is
> normal.

The array was not started automatically, after the Wizard create it?
You had to go to Disk->Maintenance and hit the Start button?
Anyhow, it is now rebuilding.

My tests were done with old 40GB disks, I don't remember the speed at
which is was done, but I think that 15MB/sec is a very low speed --
RAID1 rebuilds at about 50MB/sec -- are you using a USB hub? A good
USB disk or USB enclosure?
Even at 50MB/sec it would take about 12hours

Somebody reported (in the Hack Forum?) having RAID5 working under Alt-
F, I don't remember complains about rebuilding speed.


> tks jcard.

[Nasp]

The arrays start automatically is a rebuild too!

Runing a USB disk on a new usb enclose from Verbatim...

http://www.verbatim-europe.co.uk/en_1/product_external-hard-drive-usb-2-0-2tb_51_0_16174__162.html

And yes an USB2.0 hub too. But is only the Verbatim disk that are
connect!

The tree disks are identically!!! 2tb drives from Samsung HD204UI 32mb
de cache.

[Joao Cardoso]

On May 5, 2:30 pm, Nasp <nasp2...@gmail.com> wrote:
> Initial creation is my situation....
>
> Now more than 16hours of creation the rebuilding state is at 50%....

Is no news good news?

I'm curious to know if you managed to get it working, if any issues
appeared, performance... do you mind sharing?

BTW, have you read the "Filesystem and disk layout performance on
0.1B4" post?

http://groups.google.com/group/alt-f/browse_frm/thread/6165b89e775f6ead#

Thanks

[Nasp]

well, the raid 5 works about 3 ou 4 days. Like i say before my
intentions is to connect and desconnect usb devices.

Because that i discover that the raid5 is not ideal for my situation.
At the moment that the kernel change the letters from the third disk
in the raid setup, after connect on usb disk, the raid enter in the
degraded mode. I changethis and now i have the two internal disks in
standard mode.

I manage the backups from alt-f web interface from sda2 to sdb2. I
lose more space it that, but it is ok. I have to live it that :)

The disks are in ext3 because is more standard, the speed it is not
real important to me, but the possibility that connect pen and disks,
and that the disks have the possibility do spindown also.

[Joao Cardoso]

On May 29, 7:50 pm, Nasp <nasp2...@gmail.com> wrote:
> well, the raid 5 works about 3 ou 4 days. Like i say before my
> intentions is to connect and desconnect usb devices.
>
> Because that i discover that the raid5 is not ideal for my situation.
> At the moment that the kernel change the letters from the third disk
> in the raid setup, after connect on usb disk, the raid enter in the
> degraded mode. I changethis  and now i have the two internal disks in
> standard mode.

hmm, I see.

-When there was no second USB disk did everything runs OK?
-With a second USB disk you had to go to the RAID page and add the
missing raid component?
-Or the missing raid component was found and resyncing begins
automatically?
-Did it took too much time to accomplish?

In my tests I use old 80 and 40GB disks, so I might not noticed that
kind of issues, as resyncing could be too fast.

That's a pity that you didn't report when you detected the problem, as
I could try to diagnose and fix the issue with your help.

Thanks