Originally Posted by micksh
Andrea, please correct me if I'm wrong. Is there limitation on number of exclude entries? Can some exclude paths be present in config but missing on hard drive?
Your rules are almost correct. There isn't the need to repeat the path of the disk. Something like the following is enough:disk d1 c:\\fs\\1A\\de\\Shares\\
disk d2 c:\\fs\\1B\\de\\Shares\\
Also, there is no limit of exclude rules, and you can exclude also not existing paths, use globbing chars like * and ?, single dir/file name, or complete paths.
- Block-level checksum is an addition to parity, right? Can it happen that there will be no room for parity? For example, if I have 2TB parity disk and 2TB data disk that is filled to the end.
The checksum are placed in the another file called "content", and not in the "parity" file. If you place it in the parity disk, it reduces the space available for parity.
But in my 7x2TB array is 2GB. Not really a problem. In case, you can put it in another location and not in the parity disk.
- In some cases when one disk is close to be full WHS may move data from that disk to another. So, file from c:\\fs\\1A\\de\\Shares\\S1\\file1.ext will become c:\\fs\\1B\\de\\Shares\\S1\\file1.ext
Will this break parity? (We can't control this and BTW, this was handled in FlexRaid, Brahim developed some code especially for such case)
If a file is moved to another disk, the parity has to be recomputed. Theoretically you can skip the computation if the allocated parity of the file is not yet used in the destination disk, but I do not see a general solution to always avoid it.
Anyway, it could be an interesting optimization for the cases where it's possible.
- Can I specify restore path different to what failed disk was?
For example, if my failed disk was c:\\fs\\1A\\de\\Shares\\ and I replace it with a new disk it will become c:\\fs\\1C\\de\\Shares\\
Ideally, I need to be able to restore files into arbitrary path of my choice, and then copy them to WHS pool in order to preserve WHS tombstone integrity.
If you want to restore in a different disk, you need only to change the disk path in the configuration file.
- Memory requirements and block size. From documentation:
For example with 6 disk of 2 TiB and a block size of 256 KiB (1 KiB = 1024 Bytes) you have:
RAM = (6 * 2 * 2^40) * 24 / (256 * 2^10) = 1.1 GiB
That means it will not fit into 2GB address space if I have 12 2TB disks, right? I will have to increase block size. And then what happens if I have a lot of small files?
If you cannot use a Windows x64 version, yes. You are limited by the Windows 2GB limit. There is a Windows boot option to increase it to 3GB that could be useful in your case.
Otherwise you have to increase the block size and you are going to waste some space in the parity that may fill-up before the data disk.
To get an estimation of the wasted space, you need to count the number of files in each disk. You can approximatively assume that in each disk you lose half of the block size for each file.
For example, if in a disk you have 10000 files, and the block size is 256KB, you lose approximatively 1.28 GB in this disk.
An obvious solution is to use a little bigger disk for the parity.