Is Shared storage provided by VirtualBox better or as good as Openfiler ?

Question

Grid version : 11.2.0.3
Guest OS           : Solaris 10 (64-bit )
Host OS           : Windows 7 (64-bit )
Hypervisor : Virtual Box 4.1.18
In the past , I have created 2-node RAC in virtual environment (11.2.0.2) in which the shared storage was hosted in OpenFiler.
Now that VirtualBox supports shared LUNs. I want to try it out. If VirtualBox's shared storage is as good as Openfiler , I would definitely go for VirtualBox as Openfiler requires a third VM (Linux) to be created just for hosting storage .
For pre-RAC testing, I created a VirtualBox VM and created a Stand alone DB in it. Below test is done in VirtualBox's LOCAL storage (I am yet to learn how to create Shared LUNs in Virtual Box )
I know that a datafile creation is not a definite test to determine I/O throughput. But i did a quick Test by creating a 6gb tablespace.
Is the duration of 2 minutes and 42 seconds acceptable for a 6gb datafile ?
SQL> set timing on
SQL> create tablespace MHDATA datafile '/u01/app/hldat1/oradata/hcmbuat/mhdata01.dbf' SIZE 6G AUTOEXTEND off ;
Tablespace created.
Elapsed: 00:02:42.47
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
$
$ du -sh /u01/app/hldat1/oradata/hcmbuat/mhdata01.dbf
6.0G   /u01/app/hldat1/oradata/hcmbuat/mhdata01.dbf
$ df -h /u01/app/hldat1/oradata/hcmbuat
Filesystem             size   used  avail capacity  Mounted on
/dev/dsk/c0t0d0s6       14G    12G   2.0G    86%    /u01

Answer 1

well once i experimented with Openfiler and built a 2-node 11.2 RAC on Oracle Linux 5 using iSCSI storage (3 VirtualBox VMs in total, all 3 on a desktop PC: Intel i7 2600K, 16GB memory)
CPU/memory wasnt a problem, but as all the 3 VMs were on a single HDD, performance was awful
didnt really run any benchmarks, but a compressed full database backup with RMAN for an empty database (<1 GB) took like 15 minutes...
2 VMs + VirtualBox shared disk on the same single HDD provided much better performance, still using this kind of setup for my sandbox RAC databases
edit: 6 GB in 2'42" is about 37 MB/sec
with the above setup using Openfiler, it was nowhere near this
edit2: made a little test
host: Windows 7
guest:2 x Oracle Linux 6.3, 11.2.0.3
hypervisor is VirtualBox 4.2
PC is the same as above
2 virtual cores + 4GB memory for each VM
2 VMs + VirtualBox shared storage (single file) on a single HDD (Seagate Barracuda 3TB ST3000DM001)
created a 4 GB datafile (not enough space for 6 GB):
{code}SQL> create tablespace test datafile '+DATA' size 4G;
Tablespace created.
Elapsed: 00:00:31.88
{code}
{code}RMAN> backup as compressed backupset database format '+DATA';
Starting backup at 02-OCT-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=22 instance=RDB1 device type=DISK
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=+DATA/rdb/datafile/system.262.790034147
input datafile file number=00002 name=+DATA/rdb/datafile/sysaux.263.790034149
input datafile file number=00003 name=+DATA/rdb/datafile/undotbs1.264.790034151
input datafile file number=00004 name=+DATA/rdb/datafile/undotbs2.266.790034163
input datafile file number=00005 name=+DATA/rdb/datafile/users.267.790034163
channel ORA_DISK_1: starting piece 1 at 02-OCT-12
channel ORA_DISK_1: finished piece 1 at 02-OCT-12
piece handle=+DATA/rdb/backupset/2012_10_02/nnndf0_tag20121002t192133_0.389.795640895 tag=TAG20121002T192133 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:25
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 02-OCT-12
channel ORA_DISK_1: finished piece 1 at 02-OCT-12
piece handle=+DATA/rdb/backupset/2012_10_02/ncsnf0_tag20121002t192133_0.388.795640919 tag=TAG20121002T192133 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 02-OCT-12
{code}
Now i dont know much about Openfiler, maybe i messed up something, but i think its quite good, so i wouldnt use a 3rd VM just for the storage.