Hard Disk Options for SIMATIC IPC
Minimizing downtimes, increasing availability
The right hard disk option for your application
Depending on the chosen type of Industrial PC you can select between different hard disk options when configuring your SIMATIC IPC.
In this way the SIMATIC IPC can be equipped to meet the requirements of the respective application as well as the environmental conditions. Hard disk options may be chosen to increase availability and avoid data loss as well as to optimize performance and storage capacity. Maintenance free hardware solutions and media resistant to harshest environmental conditions are also possible.
Option RAID Configurations
The term RAID stands for "Redundant Array of Independent Disks". In the past, the development of RAID systems and RAID concepts always pursued three - sometimes opposing - targets:
Increase of the system availability through redundant data storage including automated rebuild mechanisms
Increase of the storage capacity through multiple hard drives connected in an array
Increase of the performance through parallel write and read operations on multiple drives
Depending on the weight given to one of these points, varying concepts were developed and simply numbered sequentially. Thus, a higher number following the term RAID does not mean more safety. With the development of increasingly larger and faster hard drives, the emphasis has moved toward system availability. Level 1 and Level 5 are the most widely used, with Level 5 generally being employed in larger systems with separate RAID controllers and extensive drive arrays of file and application servers. RAID Level 1, on the other hand, also provides standalone systems and client computers with a significant increase in availability
SIMATIC IPCs with RAID1/RAID5 configuration ensure increased data security: Data continues to be available, even if a hard disk fails. Loss of data is thus avoided, the system continues to be operational, and the hard disk can be replaced during operation. The onboard RAID controller saves one slot, which can be used for other cards.
Option RAID 1 configuration (mirror disk system)
RAID 1 is used exclusively for data protection, with the data being written to two drives in parallel. The mirroring of the data requires double the storage space but provides complete redundancy.
The automatic, redundant data management (data mirroring) with RAID 1 during PC operation is recommended to protect against data losses and to minimize downtimes in case of physical damage (head-crash, overheating, etc.) to the storage medium.
The major advantage of a RAID system lies in its ability to keep the system running without interruption and costly downtimes in the case of a malfunction (fail-over-capacity). However, if hard drive data is damaged or destroyed through operating errors, faulty software components or viruses, a RAID system does not offer any protection, since all write operations take place simultaneously on both hard drives. As a protection against this threat a backup of the configuration and data on an external storage medium via SIMATIC PC/PG Image & Partition Creator is recommended.
The advantages are:
Protection against data losses in case of hard drive failure
RAID 1 provides extensive protection against data losses in the case of a hard drive failure. Every write operation to one hard drive of the PC is performed in parallel on a mirror drive, so that identical hard drive contents are available at any one time. The simultaneous failure of both hard drives is rather unlikely.
Protection against downtimes
In the case of a problem with one hard drive, the application will continue to run without interruption. The functions of the “productive” drive are assumed by the mirror drive. The user can continue to work until a self-defined service date, at which the faulty hard drive can be replaced. However, during this timeframe, no increased availability exists.
Easy restoring of data on the replacement drive
If one of the two hard drives has to be replaced, the newly installed hard drive will be integrated into the RAID1 functionality – the mirror data is then automatically copied (auto-rebuild)
Option RAID 5 configuration (block striping with distributed parity)
RAID 5 not only distributes the data block-by-block across the drives in the array, but also the parity information. A separate hard drive for the parity information is not needed. RAID 5 offers a good synthesis of performance, redundancy and storage space utilization.
All data and parity information are saved on at least three hard disks.
The advantages are:
Option Second hard disk
The option Second hard disk is the ideal solution for a periodic data and above all configuration backup solution via hard drive images. If the hard drive content is damaged or destroyed through operating errors, faulty software components or viruses, the functioning state of a hard drive can quickly and easily be restored via reconstruction without lengthy system downtimes.The security of the data stored on the hard disk is one of the foundation stones of system availability.
The use of a second hard disk offers the following benefits to the user:
Quick, easy data backup
By copying or applying conventional backup-restore routines, the data of the “work” drive is duplicated on the second “backup” drive. If, for example, an operating error damages the data on the work drive, it could quickly be restored from the backup drive.
Backup of hard drive partitions
With a hard drive image software, such as the SIMATIC IPC Image & Partition Creator, entire hard drive partitions of the work drive can quickly and easily be stored as files on the second hard drive. Should the work drive malfunction, these files can quickly and precisely restore the partitions – even on a replaced hard drive. This approach is recommended, for instance, if the hard drive is split into multiple user-specific or task-specific partitions, that are to be backed up independent of each other.
Setting up an identical hard drive image
With a hard drive image software, such as the SIMATIC IPC Image & Partition Creator a precise data image of the complete work drive can quickly and easily be placed on the second hard drive, creating an identical image of the work drive. In the case of a malfunction with the wok drive, the second hard drive could quickly be changed into the work drive.
Optionally there are two hard disks with the Rack PC, also in a user-friendly removable rack for fast and easy data backup.
Option Solid state disk or Flash Drive
System availability can be further increased with a CompactFlash drive (flashdisk) or Solid State Drive (SSD) instead of a hard disk.These rugged bulk memories are approved for higher vibration, shock and temperature values and offer an availability which is significantly higher than that of a hard disk. They provide safe protection for your operating system and application.The SIMATIC IPC CompactFlash cards with up to 8 GB capacity and solid-state drive in Single Level Cell-architecture (SLC) with 32 GB are system-tested with SIMATIC IPCs.
It is possible to order the CompactFlash memory either accessible externally so that it can be swapped, or integrated so that it is protected against access.