Highly Reliable Systems: Removable Disk Backup & Recovery

Monthly Archives: December 2017

Case Study: Using High-Rely NetSwap devices for Archiving Arcserve UDP appliances

December 19th, 2017 by

Executive Summary:  Removable hard drive functionality can be added to Arcserve UDP appliances by installing a NetSwap device on the network.  This provides additional drive redundancy and can be used as an alternative or supplement to cloud storage.

Case study results:  A customer using a NetSwap 300 in NAS mode (shared CIFS hard drives) used two 10TB SATA hard drives in High-Rely classic trays and setup an Arcserve job to replicate all data stores to the NetSwap shared drive.  The customer configured the NetSwap to use “Deltasync” between the two drives.  Deltasync works independently and transparently to the Arcserve platform and creates incremental block level copies between the first and second drive. The client was able to create removable copies of a deduped 6.72TB data store with an average job run time of about 10 hours.

Configuration details:    The customer is backing up a total of 37TB on several servers.  Much of the data is Autocad so while compression is not particularly high the Arcserve platform is able to reduce the size of the data store to an impressive 6.72TB. The NetSwap 300 used a single Gigabit Ethernet card for connectivity to achieve the speeds quoted. A NetSwap 350 is available with 10GigE connectivity if more speed is needed.


Note that the UDP data is replicated twice.  Once is initiated by Arcserve and the second is continuous & initiated by the Netswap.  So
1) in this case was a Friday Arcserve replication from UDP to NetSwap.




2) the deltasync mirror from Top to bottom drive in the NetSwap.

The client swaps the bottom drive on Mondays, giving time for both jobs to complete and data to be quiescent before a drive swap.  The customer states the drive could easily be swapped daily if data set were a bit smaller, but for safety chooses to do it weekly.

The customer says that the initial Deltasync job to the second hard drive in the NetSwap took 21 hours to a blank hard drive but now the incremental Deltasync jobs are taking between 8-13 hours.  Deltasync copies only changes to files in order to save time.












This is a screen shot of web browser interface of the NetSwap while deltasyncing 10TB drives.  The data is moving at around 90GB/Hr. This example was 10TB drives, Current Maximum capacity per tray is 12TB.  14TB is expected in 2018.

For clients that need even larger archival there is a High-Rely RAIDFrame with the same removable functionality with up to 24TB per removable RAIDPac.  In this configuration each RAIDPac is RAID5 protected and contains three 12TB drives.

Conclusions:  By adding a High-Rely NetSwap appliance Arcserve UDP functionality can be enhanced and large data sets can be archived locally.  Base MSRP for NetSwap 300 is $1095 and the 10TB media trays are $695 each.  Dynamic support with 3 year advance replace warranty is highly recommended on all components.  DS contract for 3 years on base NetSwap  is $440.


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NTFS large file compatibility problem between NetSwap hard drives and native windows environments

December 13th, 2017 by

Nature of problem:

Apparent compatibility problems with large files (i.e >500GB).  For example files created by StorageCraft or similar software as would occur when backing up a disk to a full to an image.   If the hard drive is NTFS formatted by any NetSwap (version 2.15d and below) and you move the hard drive from a High-Rely tray to a stand alone USB or sata port on a Windows machine it appears as if large files are corrupt.  The file shows up in explorer as only being 32KB in size on disk.  The file will not restore and if you attempt to do anything with the file (rename, copy  etc). Windows will give an error.

By default versions 2.15d and before stored files as sparse files and those files when large became highly fragmented, leading to the apparent compatibility problem.  Version 2.15e corrects this problem by both storing files as standard file (not sparse) and also updated the NTFS driver to properly handle sparse files.  See graphic under Disk properties.   If you don’t need sparse files leave the new feature turned off.  You also have the option of switching from the default NTFS driver to the NTFS-3G driver if you have further compatibility or other issues.   For best performance and support you should leave the NTFS-3G option unchecked unless you have reason to believe there are issues with the High-Rely native NTFS driver.

If you are concerned about compatibility of large files created with versions prior to 2.15e you may wish to proactively re-create those files by doing a new full backup.  However, many customers may elect to take not action at this time because the files are not technically corrupt and will work as long as they are used or restored in the NetSwap environment.  The only issue is when the drives are removed from the NetSwap and installed directly in a windows machine (sata or usb port).  If the end user anticipates an emergency situation where restore may be done from a natively connected high-rely drive we advise recreating any files larger than about 500GB to be safe.

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