Koozali.org formerly Contribs.org

SME et choix RAID5 ou RAID1...

Offline STRyk

  • ****
  • 174
Re: SME et choix RAID5 ou RAID1...
« Reply #15 on: June 29, 2020, 04:03:35 PM »
Quote
You only have a single boot drive. SME will always create a RAID 1 mirror even on a single drive and leave it with a 'failed' drive.
You could create the base system with JUST the No Raid option. Alternatively, and for a stress free existence, get another drive and make the main system live on a proper mirror. (This is in the Wiki)
Oui, merci je connais cette option, je l'ai déjà utilisé mais il formate tout de même en RAID1.
Traduction :
Yes, thank you I know this option & I have already used it but it formats all the same in RAID1 :

# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda1[0]
      255936 blocks super 1.0 [2/1] [U_]
unused devices: <none>

Pourquoi ce "[2/1] [U_]" !!!

Je ne sais pas pourquoi...
Traduction :
I don't know why...

de souvenir sur SME9 meme avec une install noraid, il va creer un raid degradé pour la partition de boot.
Il me semblait bien. J'avais tenté plusieurs options : " noraid" "raid=noraid" ...

Merci pour l'avis au sujet du spare.
Traduction :
Thank you for the advice about the spare.

Quote
This is an excellent article on your problem.
https://www.zdnet.com/article/why-raid-6-stops-working-in-2019/
Thanks, I will read this article.

Pour le RAID6, il va falloir plus de disque et ce n'est pas à l'ordre du jour. :(
Traduction :
For RAID6, we will need more disk and it is not on the agenda. :(

Sinon : Aucune possiblité de placer le système sur un volume RAID 1+0 ?
Traduction :
Otherwise: No possibility of placing the system on a RAID 1+0 volume ?

Offline ReetP

  • *
  • 2,872
Re: SME et choix RAID5 ou RAID1...
« Reply #16 on: June 29, 2020, 04:30:59 PM »
I think you can create a 4 drive RAID 6??? Check that. It gives you 8Tb. 2 working and 2 for parity. Slower than RAID 10 but a bit more fault tolerant.

Putting the whole system on RAID 10 (or RAID6)?

Probably, but you have to use an advanced setup. Or download CentOS 6, partition it as you want, and convert it to SME

I think there is either a how to or contrib that does this but I can't find it. Jean Philippe will know.

Some other notes while you are here - we maybe ought to offer some more options on install for the future.

https://wiki.contribs.org/Raid

Another alternative - get a good hardware raid card - with some battery backed write cache.
...
1. Read the Manual
2. Read the Wiki
3. Don't ask for support on Unsupported versions of software
4. I have a job, wife, and kids and do this in my spare time. If you want something fixed, please help.

Bugs are easier than you think: http://wiki.contribs.org/Bugzilla_Help

If you love SME and don't want to lose it, join in: http://wiki.contribs.org/Koozali_Foundation

Offline STRyk

  • ****
  • 174
Re: SME et choix RAID5 ou RAID1...
« Reply #17 on: June 29, 2020, 04:42:51 PM »
Pourquoi pas votre idée avec Centos et le convertir en SME mais j'ai peur de partir dans des heures de travail pour aboutir à plein de soucis et devoir vous solliciter tout les jours :(
Traduction :
Why not your idea with Centos and convert it to an EMS but I am afraid of leaving in working hours to end up full of worries and having to ask you every day :(

OK, je vais étudier les atous entre RAID10 et RAID6 avec mes 4 disques 8To.
Traduction :
OK, I will study the advantages between RAID 10 and RAID 6 with my 4 8TB drives.

La prise en compte du RAID 1+0 à l'installation de SME serait vraiment intéressant...
Traduction :
Taking RAID 1+0 into account when installing SME would be really interesting ...

Another alternative - get a good hardware raid card - with some battery backed write cache.
J'ai eu une carte RAID5 mais le formatge est toujours lié au hardware. SME pour ça est très intéressant si la carte casse, avec SME ca ne pose pas de problème.
J'ai une carte RAID sur Mac aussi, déplacer les disques de la carte aux ports de la machine ne posent pas de problème, mais sur SME elle demande un driver...
Je préfère utiliser le RAID de SME.
Traduction :
I had a RAID5 card but the format is still linked to the hardware. SME for that is very interesting if the card breaks, with SME it does not pose any problem.
I have a RAID card on Mac too, moving the disks from the card to the ports of the machine is not a problem, but on SME it requires a driver ...
I prefer to use RAID of SME.
« Last Edit: June 30, 2020, 12:59:06 AM by STRyk »

Offline STRyk

  • ****
  • 174
Re: SME et choix RAID5 ou RAID1...
« Reply #18 on: July 21, 2020, 04:01:11 AM »
Doit on tout de même utiliser un disque avec TLER/CCTL/ERC lorsque l'on utilise SME avec un seul disque dur (donc RAID1 dégradé) ?
Merci.

Traduction :
Should we still use a disk with TLER / CCTL / ERC when using SME with a single hard disk (therefore degraded RAID1)?
Thank you.

Offline STRyk

  • ****
  • 174
Re: SME et choix RAID5 ou RAID1...
« Reply #19 on: July 21, 2020, 07:00:58 PM »
Question en plus : Comment ca se passe avec les SSD ?
TLER/CCTL/ERC obligatoire en RAID dégradé ?

Trad :
Additional question: How does it work with SSDs?
TLER / CCTL / ERC mandatory on degraded RAID1 ?

Offline STRyk

  • ****
  • 174
Re: SME et choix RAID5 ou RAID1...
« Reply #20 on: August 10, 2020, 05:22:14 PM »
Personne n'a d'idée sur cette dernière question ?

Offline ReetP

  • *
  • 2,872
Re: SME et choix RAID5 ou RAID1...
« Reply #21 on: August 18, 2020, 06:00:11 PM »
You have GOT to do some reading here. There is mountains of information out there. None of us are particularly hard drive specialists.

So I did a search.

https://en.wikipedia.org/wiki/Error_recovery_control

Quote
Standalone vs. RAID considerations

It is best for TLER to be "enabled" when in a RAID array to prevent the recovery time from a disk read or write error from exceeding the RAID implementation's timeout threshold. If a drive times out, the hard disk will need to be manually re-added to the array, requiring a re-build and re-synchronization of the hard disk. Enabling TLER seeks to prevent this by interrupting error correction before timeout, to report failures only for data segments. The result is increased reliability in a RAID array.

In a stand-alone configuration TLER should be disabled. As the drive is not redundant, reporting segments as failed will only increase manual intervention. Without a hardware RAID controller or a software RAID implementation to drop the disk, normal (no TLER) recovery ability is most stable.

In a software RAID configuration whether or not TLER is helpful is dependent on the operating system. For example, in FreeBSD the ATA/CAM stack controls the timeouts, and is set to progressively increase the timeouts as they occur. Thus, if a desktop disk without TLER starts delaying a response to a sector read, FreeBSD will retry the read with successively longer timeouts to prevent prematurely dropping the disk out of the array.

So, in standalone it is fine, but in RAID it is not.

I have no idea about SSD - you can go and read about that yourself.

This might get you started:

https://community.spiceworks.com/topic/2113677-ssd-s-for-desktop-raid
...
1. Read the Manual
2. Read the Wiki
3. Don't ask for support on Unsupported versions of software
4. I have a job, wife, and kids and do this in my spare time. If you want something fixed, please help.

Bugs are easier than you think: http://wiki.contribs.org/Bugzilla_Help

If you love SME and don't want to lose it, join in: http://wiki.contribs.org/Koozali_Foundation