Proxmox on SSD with Cold Spare HDD

[moefan]

I'm building my first production Proxmox server that I'll be using mostly for OpenVZ guests but will also have a few KVM guests also. Due to my limited budget I can not do hardware raid and wound up with a 256GB Samsung 830 SSD and 750GB WD Scorpio Black HDD. My goal is to end up with a cold spare backup disk that is synchronized once or twice a day and can be manually booted in case of disk failure.

I'm initially thinking of doing something similar to the following options but looking for advise on how to do this.

Option A:
Install all of Promox on SSD
Make a copy of root/swap on HDD and use rsync to keep current at some interval.
Make a copy of data on HDD and use Proxmox to backup guests to HDD

Option B:
Install Proxmox root/swap on HDD, but data on SSD
Make a copy of root/swap on SSD and use rsync to keep current at some interval.
Make a copy of data on HDD and use Proxmox to backup guests to HDD

 

[moefan]

I've done a little more research and setting up an LVM mirror looks like it will be a good option for the root and swap partitions. For data I do not want to reduce the performance of my guests by adding the HDD to the mirror (I'm assuming this would reduce performance of the SSD to the HDD performance). Should I do the root/swap mirror and just do guest backups to a second LVM on the HDD?

Is anyone using a SSD and HDD combo in this way?

 

[snowman66]

Proper set-up would be with hardware raid with BBU/cache.
I don't know what are you trying with swap mirror. Wouldn't be better just to add more RAM?

Can you please post pveperf for ssd and output of mount?
I tested vertex 4 v1.3 128GB on ext4 - i got 57 fsyncs/s.

 

[moefan]

I know hardware raid is the optimum solution but given my strict budget it was not an option for this server. I may do swap in memory, if not I'll do it on HDD only as to increase longevity of the SSD. Haven't built the server yet but can post performance results when completed.

 

[Jae Lee]

sort of in similar situation, but i'm not sure why your fsyncs are so low.

this is what i get from pveperf:

root@server1:~# pveperf
CPU BOGOMIPS: 166381.65
REGEX/SECOND: 1062496
HD SIZE: 54.88 GB (/dev/mapper/pve-root)
BUFFERED READS: 201.79 MB/sec
AVERAGE SEEK TIME: 0.18 ms
FSYNCS/SECOND: 2756.27

check if you have writeback cache enabled, it should be atleast over 200.

i've got the intel 520 240gb and disk space is being eat up really fast. i'm real curious to see if a cold spare HDD combo would work to consolidate both the performance of ssd's and storage of sas/sata.