jshelton Posted August 20, 2003 Report Share Posted August 20, 2003 I've been backing up about 130 GB from a RAID-5 array to DVD+R. Using the supported Sony DRU-500A drive, Windows 2000, P4 2.4GHz, 1gb RAM. Running Retrospect Professional 6.5 with latest patches and drivers. Since the backup has used 35 DVD+R media, I'm only getting about 3.7 GB per disc. Read and write speeds around around 75 MB/min, far less than expected. CPU is close to 100% busy. Since I have set Compression and Encryption (SimpleCrypt) turned on, should I expect such heavy CPU usage, and such slow performance? Why such poor capacity per disc? Perhaps 75 GB of data is TIF files - is that a factor? =John= Link to comment Share on other sites More sharing options...
natew Posted August 21, 2003 Report Share Posted August 21, 2003 Hi Once you turn on encryption, compression is automatically turned off -even if you select it. Compressing the encrypted data would actually make it grow in size which is no good. Tiff files themselves are already compressed so that could account for the size as well. If you can spare an extra disk, I would try a baseline backup with no encryption and see what kind of performance you get. What speeds do you get with other dvdR burning software? Nate Link to comment Share on other sites More sharing options...
jshelton Posted August 21, 2003 Author Report Share Posted August 21, 2003 Actually, the Retrospect manual says that HARDWARE compression is turned off when Encryption is selected, but that Software compression is still a valid choice. I agree with your idea of trying a smaller test case. I'll try that when this backup finishes (probably midway in day 5.) I have not tried non-Retrospect use of the drive lately. In fact, I had to remove a lot of other software just to get Retrospect to work. I will try slowly installing it to see if I can find some software that co-exists, but doesn't grab control all the time. Link to comment Share on other sites More sharing options...
natew Posted August 22, 2003 Report Share Posted August 22, 2003 Hi Software compression is still a valid choice but it will not work even if you turn it on. You still have to choose one or the other- compression or encryption. Nate Link to comment Share on other sites More sharing options...
paleolith Posted August 23, 2003 Report Share Posted August 23, 2003 Quote: natew said: Tiff files themselves are already compressed so that could account for the size as well. No, TIFF files are not compressed. TIFF is the uncompressed version, often used because it's the most widely compatible pixel image format. TIFFs are usually highly compressible. Perhaps you are thinking of GIF, which is indeed compressed. The OP is seeing an apparent 25% increase in file sizes. Though I'm not familiar with Retrospect encryption, this seems highly excessive to me. Have you examined the logs to make sure Retrospect is not getting errors writing to the DVD and shorting them as a result? Does the Backup Set config show all members except the last as full? Edward Link to comment Share on other sites More sharing options...
jshelton Posted August 24, 2003 Author Report Share Posted August 24, 2003 Backup set properties, Members, shows all but last disc have 4.4 GB used. (Seems strange since physical capacity is supposed to be 4.7 GB. -- BUT, it's probably just a math confusion. Retrospect may be reporting correct gigabytes (approx 1073 megabytes, 2**30 bytes) whereas stated capacity of DVDs might be 4,700,000,000 bytes I tried another backup set with Encryption on, and no compression. I got about 4.2 GB per disc, though the backup set member properties shows 4.3 GB on all but the last member. Without compression, I got much less CPU utilization. Link to comment Share on other sites More sharing options...
natew Posted August 26, 2003 Report Share Posted August 26, 2003 Hi Part of it is a math issue but there is a bit of overhead when using Retrospect to burn a disc. Nate Link to comment Share on other sites More sharing options...
drescherjm Posted September 9, 2003 Report Share Posted September 9, 2003 Quote: No, TIFF files are not compressed. TIFF is the uncompressed version, often used because it's the most widely compatible pixel image format. TIFFs are usually highly compressible. TIFF supports several different compression algorithms and the most used one was LZW which most people used even though there were patent issues with unisys. For this reason we stayed away from TIFF and GIF and use PNG. Link to comment Share on other sites More sharing options...
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