| Author | Message | ||
     Marc Vergalle Username: dobrevjetser Registered: N/A |
Hi, I'm cloning a 5 drive raid-5 of 1.4T onto an external harddisk of 2T. Now in the beginning the cloning speed was about 2000 MB/min but after several days dropped down to 800 and now even 199 MB/min. Is there an explanation for this ? Is it winhex that is doing this or is it a windows problem ? Thanks for your answer. Marc | ||
| Björn Ganster Username: admin4 Registered: 3-2004 |
I doubt that WinHex would decrease copying speed. It may be that one disk's or the chipset's heat management is reducing the transfer rate. If you have connected one of the disks via USB, it might explain the low transfer rate: USB 2 offers 480MB per second. At a speed of 2GB/min, 1.4 TB should have been copied in about 12 hours, but not several days. | ||
| Marc Vergalle Username: dobrevjetser Registered: N/A |
The target disk is connected via USB. But its the degradation in speed that makes me wondering. Marc | ||
| Pánczél, Levente Username: panczel_levente Registered: 1-1997 |
I assume that XWF is computing the 'speed' as the "average speed of the completed part of the operation" i.e. [MBs done]/[MINs elapsed]. My assumption is because operations tend to start fast because of caches (say speed A) and then continue from one point with a lower speed (say speed B) which then stays almost constant (hard disks are usually slightly slower towards their rear sectors). By such operations I have observed that after the speed has fallen from A to B XWF displays a decreasing speed-rate (in an 1/X like fasion). So maybe your system is working at a nearly constant rate. To verify current speeds I always use Windows' Task manager: one can make 'I/O read bytes' and 'I/O write bytes' columns appear and watch the values change for the xwforensics.exe process of interest. | ||
| TOM_C_A_T Greeneye Username: tom_c_a_t Registered: N/A |
Initial Speed was 2000MB/Min, right ? means 34mb/s, approx. Which external USB drive does give that much speed ? I don't think so. It would shouldn't be more than 25mb/s. ( as you are using RAID ) in addition to, I'm also agree with opinions of Marc n Levente. | ||
| Duncan Clarke Username: dac_retrodata Registered: N/A |
34mb/s on external USB on the PC is quite feasible. However, on a Mac you realistically get 50MegaBytes per second on USB - sustained. Windows overhead, etc... Duncan (Definitely not a Mac cult member...) | ||
| Ross Johnson Username: rjohnson Registered: 7-2004 |
WHF 15.1 SR-8 (and others) Even on healthy drives, the displayed transfer rate (i.e. xxx MB/min) in the dialog box will drop dramatically after a few million sectors, even though the "Transferring sectors ... (No. xxxxxx) still appears to growing at the same rate. I Have learned to ignore this but would love to see it addressed for an SR-9? The display initially displays all digits (e.g. 2000 MB/min) but eventually drops to 0 MB/min then slowly grows again to a few hundred, then drops to zero again and then repeats the cycle until the clone is done (all the while the "Transferring Sectors ..." is still growing fast) At first I thought maybe the 2000 MB/min was being truncated at the front as the rate went up and the data was perhaps to close to the leaqding edge of the dialog box. But I later ruled that out after noting the cyclical pattern. In addition, the approx. xxx mon. left is accurate based on the speed that was initially displayed (this is applies to healthy drives). These days I manually monitor, time and calculate to stay appraised of the health of the source drive. I use (and assume as accurate) the percentage indicator and time remaining display. Any chance this could be looked into? And, if confirmed, a 15.1 SR-9 with the fix? Thank you, Ross@WinPro.net | ||
| Stefan Fleischmann Username: admin Registered: 1-2001 |
And does this happen only with [ ] Simultaneous I/O unchecked? Then I might have an explanation and could fix it. Or maybe only when checked? | ||
| Ross Johnson Username: rjohnson Registered: 7-2004 |
> And does this happen only with [ ] Simultaneous I/O unchecked? I leave it unchecked most of the time (and I observe the issue when it is unchecked). It may occur while checked, but I do not use that option often enough to recall for sure. Thank you, Ross@WinPro.net | ||
| Stefan Fleischmann Username: admin Registered: 1-2001 |
OK, so in the next service releases it will probably not occur any more. |