Using rsync backups on the Thecus N8800 NAS
Part I - Thecus N8800
Having just upgraded an old Netgear ReadyNAS NV+ to the Thecus N8800 I wanted to try out on some existing rsync backup jobs. This unfortunately wasn't as straightforward as I had hoped, but nevertheless, I got it working.
First some quick specs on the N8800
- CPU - Intel Celeron M @ 1.86GHz ( 3736 BogoMIPs )
- 2GB RAM ( as purchased )
- OS stored on internal SSD
- 8 hot-swap SATA I/II drive bays, 1 external eSATA connector
- 1 serial port for UPS ( APC SmartUPS and many others )
- 2 hot-swap redundant power supplies.
- 2U rack-mount
- JBOD, and RAID 0, 1, 5, 6, 10 supported
- EXT3, XFS, and ZFS (fuse) file systems supported
- 2 Ethernet ports ( LAN +WAN ) or link aggregation
- Protocols: SMB/CIFS, HTTP/HTTPS, FTP, NFS v3, AFP
- iSCSI target, supports MsWindows, Linux, ESX
- Auth: Local user/group, or Windows AD
- Drives: I'm using 5X Seagate Baracuda 7200.11 (1.5GB SATA II) - ST31500341AS ( Firmware CC1H)
users still have problems with some drives listed on the compatibility list ( like WD green drives )
Firmware upgrades may be required if you get an older drive.
Some online users had reported sporadic heat problems with earlier Thecus tower units. However, the rack-mount N8800 has 4 large hot-swap 80mm internal fans that provide plenty of cooling for the drives and CPU.
As far us using the system, note that many file system operations ( creating a file system, expanding a RAID array ) etc. can be expected to take a long time ( 5 to 25 hours ) . This isn't that unusual for large NAS arrays.
There are a couple of surprises that I wish I had known more about. Most of these are actually covered in fine print in the manual.
- The admin password doesn't work with special characters (!@#$). The N8800 accepts the password change, but then won't let you login to the unit, and you'll have to use a special USB reset sequence to erase the password !
- When using ZFS you can have only a single ZFS file system. ZFS doesn't support NFS services ! (WTF)
ZFS however does permit snapshots of the data volumes ( but not iSCSI volumes ). Since ZFS is a user space deamon (using FUSE) it doesn't have great performance. Personally I think that ZFS needs to be run in kernel space from a Sun kernel to have good performance. When you add the drawbacks to ZFS above it just isn't very useful on the N8800 unless you need snapshots on a NAS file share over CIFS.
- Each volume is limited to 5 iSCSI targets.
- SSHD is not supported out of the box, you can add the unsupported SYSUSER and SSHD modules below to obtain root access to the box.
- Out of the box, both RSYNC and the Thecus proprietary NSYNC ONLY WORK TO ANOTHER N8800 BOX ! You can add the unsupported RSYNC module below to get a normal rsync deamon running. I can't imagine why this limit is here other than to attempt to lock you into using the Thecus product line.
Note: the recent manual/firmware may have improved the rsync situation - more later.
For more pictures wee Tom's Hardware review .
Interoperability with VMWare ESX 4.0
I tried mounting the Thecus iSCSI target on a single ESX 4.0 server and had no issues mounting the LUN or running a test VM. I've not had time to evaluate performance, but roughly a 4 disk RAID 5 XFS iSCSI LUN looks to have roughly the same performance of JBOD internal disks on an ESX host.
I'm not using the Thecus iSCSI target with an ESX cluster - so I do not know if the iSCSI target supports multiple mounts by each ESX hosts in the cluster.
The N8800+ also supports thin-provisioning ( or NOT ) of each iSCSI target. The thin-provisioning menus are rather cryptic. You first have to create a thin-provisioned pool and then provision space and an iSCSI target inside the pool. The pool is just called 'thin provision' however, and I also suspect that it is using ZFS which would negatively impact performance.
Note: Now that ESX 4.0 natively supports thin-provisioning, ESX appears able thin provision using the normal iSCSI target on the Thecus - so this may be the way to go. ( Untested )
I had some early instabilty issues with iSCSI disconnecting from ESX ( this may have been my fault due to the poor menu's/documentation ) but since have switched to NFS, so I can't say for sure.
NFS mounts to ESX 4.0 also support thin-provisioning and don't need to be pre-allocated, so this may be the preferred way to go. ( Note NetAPP filers that support both iSCSI and NFS highly recommend using NFS with ESX ). I've been running several ESX production VM's over the Thecus NFS mounts now for several months with no issues.
Thecus N8800 Modules
To add sshd, and rsync capability to the N8800 there are unsupported modules here:
I've verified that all (3) modules work on my N8800 ( with firmware 3.01.01 )
- N5200 SYSUSER 2.00.02
- N5200 SSHD 2.00.00
- N5200 RSYNC 2.00.01
Backing up to the Thecus N8800 using rsync
First in the Nsync target screen enable the Rsync target server and setup a user and password for Rsync.
The rsync config file is located at /tmp/rsync.conf, and you will notice that a RSync module is created named "rsync_backup"
So to rsync a local directory to the Thecus at 10.0.0.10
rsync -av /localdir email@example.com::rsync_backup/destdir
Backing up to the Thecus using dpbackup (duplicity)
For backing up laptops or PC's I've written a wrapper around duplicity that adds email notices, logs status to disk, and makes restores easier.
My Dpbackup.sh script can be downloaded from the Perforce public depot. (Click 'depot path' link at top right corner ).
In the script change DP_DESTINATION to: