Dell R720 Display problem with Fedora 26 server
-
@francesco-provino do you know how to bypass the HW RAID in DELL R720?
I want to use SW raid instead with MD.Thanks.
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
@francesco-provino do you know how to bypass the HW RAID in DELL R720?
I want to use SW raid instead with MD.Thanks.
Several points here....
- R720 doesn’t have hardware RAID. There is an add on PERC controller in it. That’s where the RAID lives. The server itself doesn’t have any. So all RAID questions would be about the card.
- PERC controllers don’t have a bypass option. You remove the card to bypass. The work around is to make each drive attached to the card it’s own RAID array.
- You without question don’t want to do this. There is no scenario where this is a good idea for you. Do not go down this path. MD is not a good idea here.
-
thanks.Will continue my experiment. I guess I stuck with PERC RAID then.
-
- Setup RAID-1 via PERC for 2 x 4TB HDD
- Install Fedora 26 Server from USB Boot
- LVM only 20GB out of 4TB for Fedora VM Host (Xen/KVM)
- Partition :
- root (LVM with xfs) 17GB
- boot (LVM with xfs) 1GB,
- swap (LVM with swap) 2GB
Please correct if my setup is fine. still learning
Should I partition 20GB and leave the free space for VM guest LVM? or I do 4TB during the install, and put VM host as image file?
CMIIW.Thanks.
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
@francesco-provino do you know how to bypass the HW RAID in DELL R720?
I want to use SW raid instead with MD.Thanks.
I agree with Scott here. If the PERC is already in place, you can’t beat it with an HDD-only setup. Stay with the PERC.
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
- Setup RAID-1 via PERC for 2 x 4TB HDD
- Install Fedora 26 Server from USB Boot
- LVM only 20GB out of 4TB for Fedora VM Host (Xen/KVM)
- Partition :
- root (LVM with xfs) 17GB
- boot (LVM with xfs) 1GB,
- swap (LVM with swap) 2GB
Please correct if my setup is fine. still learning
Should I partition 20GB and leave the free space for VM guest LVM? or I do 4TB during the install, and put VM host as image file?
CMIIW.Thanks.
You have to choose between storing the VM in LVM partition directly or in files. LVM is very solid and a little faster. The file backend is also solid today, and a lot more flexible; I suggest to use XFS as a base filesystem.
PV the whole disk array anyway.Remeber, both thin LVM and non-preallocated QCOW files will slow the write operations A LOT.
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
- Setup RAID-1 via PERC for 2 x 4TB HDD
- Install Fedora 26 Server from USB Boot
- LVM only 20GB out of 4TB for Fedora VM Host (Xen/KVM)
- Partition :
- root (LVM with xfs) 17GB
- boot (LVM with xfs) 1GB,
- swap (LVM with swap) 2GB
Please correct if my setup is fine. still learning
Should I partition 20GB and leave the free space for VM guest LVM? or I do 4TB during the install, and put VM host as image file?
CMIIW.Thanks.
One last thing: raid 1 on standard SATA hdd is gonna be slow. Quite slow.
-
Am i right to say better to just use the whole array on the host and locate it to root partition? and use file image instead for flexibility?
-
@francesco-provino I guess i have no choice for data sake protection. Do have any other choice? What is the best option for me?
thin lvm / cow is for sharing storage right purpose on limited disk right? by saying slow down A LOT, may i know roughly how many % slower based from you experience?
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
thanks.Will continue my experiment. I guess I stuck with PERC RAID then.
What do you mean stuck? It's a good thing. Why are you trying to work around it? There is some logic missing here. You can always remove it, but why would you?
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
3. swap (LVM with swap) 2GBI don't use swap volumes any longer. Just make a swap file on /
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
Am i right to say better to just use the whole array on the host and locate it to root partition? and use file image instead for flexibility?
Of course, you never use anything but file image.
-
@scottalanmiller i mean i want to experiment between perc and sw raid to learn the diff... so i guess i dont have that option to play around...
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
@scottalanmiller i mean i want to experiment between perc and sw raid to learn the diff... so i guess i dont have that option to play around...
Ah, just for learning, that is fine. But RAID is RAID, it's not like you really learn much. You should learn MD in a lab, not on this hardware. You can't easily make an MD RAID array on top of the PERC using the image files to learn anything you want with MD.
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
@scottalanmiller i mean i want to experiment between perc and sw raid to learn the diff... so i guess i dont have that option to play around...
If you want to learn how to manage md, just make a virtual machine with a lot of small virtual drives. Much easier and safer if you're just wanting to learn (if you completely wipe something, it's only a vm.)
-
@travisdh1 said in Dell R720 Display problem with Fedora 26 server:
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
@scottalanmiller i mean i want to experiment between perc and sw raid to learn the diff... so i guess i dont have that option to play around...
If you want to learn how to manage md, just make a virtual machine with a lot of small virtual drives. Much easier and safer if you're just wanting to learn (if you completely wipe something, it's only a vm.)
Exactly
-
@francesco-provino said in Dell R720 Display problem with Fedora 26 server:
One last thing: raid 1 on standard SATA hdd is gonna be slow. Quite slow.
AFAIK, RAID 1 will improve read 2x ? maybe slower write but not so much?
CMIIW.
Thanks.
-
@kuyaz said in Dell R720 Display problem with Fedora 26 server:
@francesco-provino said in Dell R720 Display problem with Fedora 26 server:
One last thing: raid 1 on standard SATA hdd is gonna be slow. Quite slow.
AFAIK, RAID 1 will improve read 2x ? maybe slower write but not so much?
CMIIW.
Thanks.
Read is 2x, Write is 1x. There is no write penalty whatsoever.
-
-
@scottalanmiller yes thats what i think of. so @Francesco-Provino statement is incorrect? : One last thing: raid 1 on standard SATA hdd is gonna be slow. Quite slow.
