In this article, we take a look under the hood of the Fujitsu Eternus DX80 disk array that we use for the WEDOS Disk service.
We use Fujitsu Eternus DX80 disk arrays for our backups and also for the service WEDOS Disk .
Disk array parameters:
- 2 controllers
- 10 shelves for 3.5″ drives, all with dual and redundant power supplies and dual connections to controllers
- all hot swap components
- 120 Nearline SAS 3 TB 7.2k drives
- Gross disk capacity 360 TB
- disk groups in RAID 5+0, net usable capacity approx. 270 TB
- 2 hot spare disks (data synchronization starts immediately if another one fails)
- all components in stock for immediate replacement in case of failure
- write-back method using 2 GB cache, read cache, prefetch cache
- The cache protector uses a capacitor to keep data in memory and write it later during a power failure.
- Data Block Guard adds parity bits to all data blocks to ensure maximum data integrity on disk and in the cache.
- Eco-mode reduces disk speed, resulting in lower power consumption and reduced heat loss.
The disk array is further connected to the control servers via two paths via a SAS (6Gb/s) interface. The control server is running Linux CentOS 6.2, logical disks from storage are mounted on it, the file system is ext4 and user directories are accessible via FTP (vsftpd), rsync and SMB (samba). It also runs our production software(ServerManager), which controls everything and communicates with our other systems (ordering system, internal administration) and with the customer administration interface.
Fully equipped chassis with 3.5″ drives weighs 350kg and the maximum power input according to the manufacturer is about 5.5kW of which about 20000 kJ/h is radiated as heat.
Management
Disk array management is done via a web interface (see photo gallery). Here you create and administer RAID groups (groups of disks in a RAID), volumes (logical disks), individual components, SAS interfaces, etc.
In the management, we can also monitor the load of individual components and, if necessary, set up various types of error notifications via e-mail and SNMP. Storage allows administration at several administrative levels with different rights.
Power
As part of a comprehensive storage test, we tested the average transfer rate of the device. The testing consisted of moving a 5 GB large file from the ramdisk to the server and back via a 6Gb/s SAS interface. In both operations we achieved real speeds of over 420 MB/s.
Conclusion
We find the DX80 to be the ideal device for our purposes from the Fujitsu storage portfolio. After several months of operation, we have to say that it is a robust, stable and fast solution that has so far met our expectations. Once again, we are pleased to have chosen Fujitsu as our supplier.
