Hallo!
I need help... I don't know wheter I did something wrong or something went wrong or if this is just normal...
I made a mirror copy of an external HDD (1TB nominal capacity = 931GB real capacity, 652 GB mixed files to copy) to an external SSD (1TB nominal capacity = 931 GB real capacity).
On the SSD the mirror copy of part (most) of the original 652GB files take up all the 931 GB space on disk, saturating it and thus leaving some files behind. Each mirror file on the SSD takes up more space on disk than the original file does on the HDD.
Mirroring also deleted 3 files that were on the SSD (first put them in a trash bin, and eventually deleted them), but I guess I should have figured this out. My fault!
Besides having been unable to copy all files (39GB missing), I doubt I have enough space left for future sync... I ended up with 35MB free space!
How can I overcome the space problem? Should I delete the mirror copy and start again? Many thanks for any help or suggestion you may provide!
Besides this problem, the program is fantastic: very fast and efficient, no problems with "too long filenames" etc.
I'm using the FreeFileSync Donation Edition.
Thanks, Elena
Mirror files taking up too much space
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- Joined: 29 Aug 2018
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- Posts: 2270
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Even if disks have the same size (as you stated), and are formatted in the same way (e.g both NTFS, which you do not mention) the "Allocation unit size" (Bytes Per Cluster) might differ, depending on the formatting settings.
Files always occupy an integer amount of Clusters.
If you have a Cluster-size of e.g. 64k, even files of just a few bytes will occupy a (full) cluster, so as per the example 64k. If your HDD has a smaller cluster-size than your SSD, the same files will occupy more space on your SSD than on your HDD, particularly if you have a lot of small files.
In Windows you can check your Cluster-size of an NTFS drive (amongst others) by opening a Command prompt window ("cmd") and entering "fsutil fsinfo ntfsinfo D:"+enter (change the drive letter, here "D", according to need).
Files always occupy an integer amount of Clusters.
If you have a Cluster-size of e.g. 64k, even files of just a few bytes will occupy a (full) cluster, so as per the example 64k. If your HDD has a smaller cluster-size than your SSD, the same files will occupy more space on your SSD than on your HDD, particularly if you have a lot of small files.
In Windows you can check your Cluster-size of an NTFS drive (amongst others) by opening a Command prompt window ("cmd") and entering "fsutil fsinfo ntfsinfo D:"+enter (change the drive letter, here "D", according to need).
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- Joined: 29 Aug 2018
Thank you so much, PIerry!
I'll check it immediately. Right now I'm remembering that the HDD is certainly NTFS formatted, but the SSD might be ExFAT...!!! Ehm, I'll check it. Argh...night working is never a good idea!
Thanks again.
I'll check it immediately. Right now I'm remembering that the HDD is certainly NTFS formatted, but the SSD might be ExFAT...!!! Ehm, I'll check it. Argh...night working is never a good idea!
Thanks again.
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- Joined: 1 Aug 2018
Hi there,
My server has 6,5 Tb free space and is ntfs format also my 2 disks 1,8 Tb are ntfs. all 3 disks got a cluster size of 4096
The server raid disk is empty, so i made a batch file, the first time no problem everything fits, now i want to re-sync and the program is telling me the server is full, there should be enough space on the server ?.
So i thought i start over and delete everything from the server, but wile I'm deleting, i get the announcement " can't delete the file be course the name of the file is to long, so after deleting step by step directories i find the file ( who should be to long ) but noting wrong with the length of the name, there are files who has longer names and those i can delete.
HELP
i use the freeware program be course i don't have a credit cart, as soon as there is a ideal payment option i will donate no problem.
Greetings,
Harm Hoekstra
My server has 6,5 Tb free space and is ntfs format also my 2 disks 1,8 Tb are ntfs. all 3 disks got a cluster size of 4096
The server raid disk is empty, so i made a batch file, the first time no problem everything fits, now i want to re-sync and the program is telling me the server is full, there should be enough space on the server ?.
So i thought i start over and delete everything from the server, but wile I'm deleting, i get the announcement " can't delete the file be course the name of the file is to long, so after deleting step by step directories i find the file ( who should be to long ) but noting wrong with the length of the name, there are files who has longer names and those i can delete.
HELP
i use the freeware program be course i don't have a credit cart, as soon as there is a ideal payment option i will donate no problem.
Greetings,
Harm Hoekstra
- Posts: 10
- Joined: 24 Sep 2018
PIerry,
Great answer, one that I would never have thought of or about.
I found a useful reference:
https://support.microsoft.com/en-us/help/140365/default-cluster-size-for-ntfs-fat-and-exfat
It would appear that, for the 1TB drives (HDD NTFS vs SSD exFAT), the cluster sizes are radically different (4 KB vs 128 KB).
I was just about ready to buy a 1 TB SSD to transfer files off my very old 1 TB HDD. Will rethink this very carefully, now.
Paul
Great answer, one that I would never have thought of or about.
I found a useful reference:
https://support.microsoft.com/en-us/help/140365/default-cluster-size-for-ntfs-fat-and-exfat
It would appear that, for the 1TB drives (HDD NTFS vs SSD exFAT), the cluster sizes are radically different (4 KB vs 128 KB).
I was just about ready to buy a 1 TB SSD to transfer files off my very old 1 TB HDD. Will rethink this very carefully, now.
Paul
