Hi All,
How can I RAID 10 on install? (the names myRAID1 and myRAID2 are just for example purposes)
I select a custom layout....
/dev/sda, sdb, sdc, sdd are listed...
I create a partition of Software RAID on each of sda, sdb, sdc, sdd
Create a swap partition on sda?
Click RAID and take sda and sdc and RAID 1 to myRAID1
Click RAID and take sdb and sdd and RAID 1 to myRAID2
Click RAID and take myRAID1 and myRAID2 and RAID0 to MYRAID
This leads me down to swap. If I create swap on sda, then dont sdb, sdc, sdd then all have unused space of the size of swap on sda?
What is the rule of thumb for Swap these days. Back a long time ago it was double the RAM in the machine.....but that was a long time ago, what is best now?
Thanks for the chat! -Jason
ML wrote:
Hi All,
How can I RAID 10 on install? (the names myRAID1 and myRAID2 are just for example purposes)
3rd time this question has been asked in the past few weeks, I believe the answer is not using the normal installer. I believe if you make a custom installer with the right modules you can do it by hand in the console before the installer loads.
Another way which I've suggested and should work is use LVM to do the striping between two RAID 1 volumes, certainly not as "clean" as a real RAID 1+0, but you should be able to do it from the regular installer.
The best way is probably to use a hardware controller.
What is the rule of thumb for Swap these days. Back a long time ago it was double the RAM in the machine.....but that was a long time ago, what is best now?
Depends on your needs, I generally use 1GB of swap for most systems that have up to 4GB of ram, beyond that I use 4GB of swap for most everything else.
I do have nagios checks that will alert if the system has more than 10% of swap in use.
In my opinion swap is an emergency resource only, the performance hit is so huge that if your actively swapping 4GB your system is going to be in an unusable state.
For all of my physical systems I also set /proc/sys/vm/swappiness to 0 to reduce the likely hood of the system going into swap. Virtual systems running in VMware at least are more likely to go into swap because of memory ballooning so I don't adjust the swappiness setting on them away from the default.
nate
Nate,
How can I RAID 10 on install? (the names myRAID1 and myRAID2 are just for example purposes)
3rd time this question has been asked in the past few weeks, I believe the answer is not using the normal installer. I believe if you make a custom installer with the right modules you can do it by hand in the console before the installer loads.
Another way which I've suggested and should work is use LVM to do the striping between two RAID 1 volumes, certainly not as "clean" as a real RAID 1+0, but you should be able to do it from the regular installer.
The best way is probably to use a hardware controller.
People went back and forth on the list saying that if a hardware controller was out of the budget right now RAID 10 would be the best solution.
It seems that the installer wont let you create two RAID1 with the same mount-pount and it looks like you have to specify one. I dont see how to do this and I dont know how to make a custom installer for this.
-Jason
ML wrote:
People went back and forth on the list saying that if a hardware controller was out of the budget right now RAID 10 would be the best solution.
That is raid1+0. raid10, under md, is something else different from raid1+0.
It seems that the installer wont let you create two RAID1 with the same mount-pount and it looks like you have to specify one. I dont see how to do this and I dont know how to make a custom installer for this.
You should mark those two mirrors as raid and then use them as members of a stripe array. If you cannot do that, then you will just have to manually do it on a shell (Alt+F2) and get the installer to rescan the raid devices.
How can I RAID 10 on install?
Does anyone know if this approach: http://www.howtoforge.com/install-ubuntu-with-software-raid-10
Will work for CentOS?
Neil
-- Neil Aggarwal, (281)846-8957, http://www.JAMMConsulting.com CentOS 5.4 KVM VPS $55/mo, no setup fee, no contract, dedicated 64bit CPU 1GB dedicated RAM, 40GB RAID storage, 500GB/mo premium BW, Zero downtime
Neil Aggarwal wrote:
How can I RAID 10 on install?
Does anyone know if this approach: http://www.howtoforge.com/install-ubuntu-with-software-raid-10
Will work for CentOS?
Never tried the Centos LiveCD so I cannot say but manually creating the raid1 arrays and then striping them in a shell prior to partition does work since RH9.