General question about filesystems, LVM, etc.

astrakid

Active Member
Jun 13, 2013
72
1
28
Hi,
i am just building up my private server with proxmox.
My goal is to have proxmox installed on my "central" filesystem (it is a usb-stick, already running) and for each vm i want another usb-stick with its own filesystem. so every vm will be independent.
as far as i see i have to do this in proxmox with LVM. otherwise i can't use a stick, correct?

would it be possible, to use a stick without using LVM (i don't see a benefit using LVM when using complete usb-sticks for simple filesystems)?

the benefit is, if something fails with my server,
- i am able to take each vm and put it into another server.
- in case of a filesystem error only one vm is affected (if the proxmox-fs is affected, the point before is considered)
- i can simply switch vms with filesystems to other servers, backup them or copy them.
- the complexity is reduced, because each vm is more or less on its usb-stick

the performance is quite ok currently, so i have no need for ssd or anything like this.

kind regards,
astrakid
 
Last edited:

dea

Active Member
Feb 6, 2009
125
1
38
Hi,
i am just building up my private server with proxmox.
My goal is to have proxmox installed on my "central" filesystem (it is a usb-stick, already running) and for each vm i want another usb-stick with its own filesystem. so every vm will be independent.
as far as i see i have to do this in proxmox with LVM. otherwise i can't use a stick, correct?

would it be possible, to use a stick without using LVM (i don't see a benefit using LVM when using complete usb-sticks for simple filesystems)?

the benefit is, if something fails with my server,
- i am able to take each vm and put it into another server.
- in case of a filesystem error only one vm is affected (if the proxmox-fs is affected, the point before is considered)
- i can simply switch vms with filesystems to other servers, backup them or copy them.
- the complexity is reduced, because each vm is more or less on its usb-stick

the performance is quite ok currently, so i have no need for ssd or anything like this.

kind regards,
astrakid

Hem, USB stick is dangerous: poor reliability and few write cycles.
Are you sure ?
 

astrakid

Active Member
Jun 13, 2013
72
1
28
yes, I am. I know about the risks, but I am running an operating system on my NAS from usb, which is working ok for > 16 months now. With backups (especially from my VMs) I want to guarantee to get back to the sun in case of a failing stick quite quickly! But it is saving power (3 sticks take now about 1 watt, and writing will be minimized by writing e.g. logs to ramdisk and store them on the stick only once a day etc.). a disk will take much more, and 24x7x365 operation is necessary. starting and stopping the disk too often isn't goot for the disk as well, so i decided to use usb sticks.

kind regards,
astrakid
 

tmikaeld

Active Member
Jan 21, 2013
68
2
28
Running FreeNAS from USB is NOT the same as running proxmox from USB. When you load FreeNAS from the USB it will run in RAM and swap to RAM, while proxmox will swap and cache to harddrive (in this case USB) - the USB's write cycles will be worn out very quickly and the system will be slow. I have no clue if it's possible to change swap and cache on proxmox.
 

astrakid

Active Member
Jun 13, 2013
72
1
28
hi, thanks for the tip. swap is disabled (no swap partition, so it is set to 0), and there is 8gb of RAM available. Referring to htop the system is utilizing 3gb (not using all VMs, but i will limit them that proxmox has enough memory available).
 

pirateghost

Member
Apr 25, 2013
454
10
18
Use your FreeNAS box as the storage for your VMs...you will get better performance from that than you will a USB drive.
 

astrakid

Active Member
Jun 13, 2013
72
1
28
I don't need performance, I need a power saving system. ;)
freenas is part of the vm - respectively "fileserver" (turnkey linux). and i don't want the drive to run every time someone accesses it. so i prefer having it on the stick. an ssd would be an option as well, but costs too much - usb sticks i have everywhere.

regards,
astrakid
 

pirateghost

Member
Apr 25, 2013
454
10
18
I don't need performance, I need a power saving system. ;)
freenas is part of the vm - respectively "fileserver" (turnkey linux). and i don't want the drive to run every time someone accesses it. so i prefer having it on the stick. an ssd would be an option as well, but costs too much - usb sticks i have everywhere.

regards,
astrakid

so what will you do when you completely destroy a USB stick from writing too much? do you plan on having backups?
you should understand the limitations of USB before going down this route.
http://en.wikipedia.org/wiki/USB_flash_drive
http://en.wikipedia.org/wiki/Flash_memory
http://cfgearblog.blogspot.com/2011/03/how-long-does-flash-drive-last_22.html
 

WhiteStarEOF

Active Member
Mar 6, 2012
96
10
28
Hi,
i am just building up my private server with proxmox.
My goal is to have proxmox installed on my "central" filesystem (it is a usb-stick, already running) and for each vm i want another usb-stick with its own filesystem. so every vm will be independent.
as far as i see i have to do this in proxmox with LVM. otherwise i can't use a stick, correct?

would it be possible, to use a stick without using LVM (i don't see a benefit using LVM when using complete usb-sticks for simple filesystems)?

the benefit is, if something fails with my server,
- i am able to take each vm and put it into another server.
- in case of a filesystem error only one vm is affected (if the proxmox-fs is affected, the point before is considered)
- i can simply switch vms with filesystems to other servers, backup them or copy them.
- the complexity is reduced, because each vm is more or less on its usb-stick

the performance is quite ok currently, so i have no need for ssd or anything like this.

kind regards,
astrakid

Well, I also think this is a terrible idea, but since everyone else has posted about how it's a terrible idea and you still seem to be okay with it, let's talk about getting it working.

Without using LVM, you lose the ability to do live migration, and live backups. If you don't care about those, then all you need to do is partition and format the USB drives as you see fit, create mount points for each drive, set those drives to automatically mount to those mount points in /etc/fstab, and finally use Proxmox's storage tab to add a directory as a storage location.

That's the 30,000ft view of what you need to do. If you need help executing any of those pieces, post back and we can walk you through it. And always remember, it's never too late to reconsider this madness.
 

astrakid

Active Member
Jun 13, 2013
72
1
28
Hi,
i am aware of the limitations. Backups will be done on a weekly base.

regards
astrakid
 

snowman66

Active Member
Dec 1, 2010
254
1
38
I don't need performance, I need a power saving system

Biostar NM70I-847 + 2.5" Seagate 500 GB hybrid disk (ssd+hdd) + 8 GB RAM => Power consumption is about 20W.;)

Without using LVM, you lose the ability to do live migration, and live backups

"The new KVM live backup is targeted to work for all storage types and eliminates the need for special LVM configurations with enough snapshot space by avoiding the use of temporary storage."

http://pve.proxmox.com/wiki/Backup_and_Restore
 

astrakid

Active Member
Jun 13, 2013
72
1
28
Biostar NM70I-847 + 2.5" Seagate 500 GB hybrid disk (ssd+hdd) + 8 GB RAM => Power consumption is about 20W.;)
I have an Msi 847 in use with 8gb ram -> 18w with 3 USB Sticks attached.


"The new KVM live backup is targeted to work for all storage types and eliminates the need for special LVM configurations with enough snapshot space by avoiding the use of temporary storage."

http://pve.proxmox.com/wiki/Backup_and_Restore

Have to Check that later.Thanks nevertheless.

Regards astrakid
 

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