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#31
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Raid0 or Raid5 for network to disk backup (Gigabit)?
"Arno Wagner" wrote in message
In comp.sys.ibm.pc.hardware.storage markm75 wrote: On Apr 4, 12:31 pm, "Maxim S. Shatskih" wrote: Keep in mind that any application that writes enormous files to a Windows network share will experience gradual but steady performance degredation over time. This is due to a performance bug in the Windows itself, and has nothing to do with the application that is writing the data. This can be easily reproduced by writing a simple app that does nothing but constantly write a continuous stream of data to a specified file. Exactly so, we have noticed it and measured it. This is MS's issue, and is possible related to cache pollution - polluting the cache faster then the lazy writer will flush it. Tweaking the cache settings in the registry (after finding the MS's KB about them) can be a good idea. the backup image into ~50GB pieces. Most backup apps support splitting the backup image file. ShadowProtect surely supports this, and I think Acronis and Norton Ghost/LSR too. -- Maxim Shatskih, Windows DDK MVP StorageCraft Corporation Thanks for that tid bit.. I'll either break them up and test again or try to find the MS solution. Sure enough, ShadowProtect ended up at 9 hours as well. Well, that would explain it. Once again. MS is using substandard technology. I hope you find a solution to this, but I certainly have ni clus what it could be. Not uncommon when you have so many brainfarcts as you have. babblebot. Arno |
#32
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Raid0 or Raid5 for network to disk backup (Gigabit)?
"Arno Wagner" wrote in message
In comp.sys.ibm.pc.hardware.storage Maxim S. Shatskih wrote: Well, that would explain it. Once again. MS is using substandard technology. I would not say that SMB slowdown on files 100GB is "substandard" for a mass market commodity OS. Hmm. I think that if it supports files 100GB, then it should support them without surprises. Of course, if you say ''commodity'' = ''not really for mission critical stuff'', then I can agree. This is a rare corner case in fact, with the image backup software being nearly the only users of it, and they can split the image to smaller files. Note that lots of UNIX-derived OSes still have 4GB file size limit :-) I wouldn't know. Linux ext2/3 has a 2TB file size limit. But that was actually not my point. My point is that if it is supported, then it should be supported well. If it is not supported that is better than if you think you can use it, but on actual usage things start to go wrong. Nothing goes 'wrong', you babblebot moron, it only gets slow. I believe this whole thread shows that ;-) What this thread shows is that you don't know anything, babblebot, that you are just feeding on others for information to badmouth MS, you Lunix zealot. So ''substandard'' = ''the features are there but you should not really use them to their limits'', a.k.a. ''we did it, but we did not really do it right''. It's the OS showing it's limits, not the file system. Arno |
#33
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Raid0 or Raid5 for network to disk backup (Gigabit)?
Maxim S. Shatskih wrote:
I wouldn't know. Linux ext2/3 has a 2TB file size limit. Sorry. See the cite from include/linux/ext2_fs.h below and "__u32 i_size;" in it. ext2's limit is 4GB. I remember ext3 being compatible with ext2 in on-disk structures in everything except the transaction log, so, looks like ext3 is also limited to 4GB per file. Don't be silly, even a minimal amount of checking would have shown this to be false for a long time now. The exact file size limit for ext2/ext3 depends on blocksize, with the default 4 kB it's 2 TB (and it's been rare to see any other blocksize for a long time now). IIRC at least (some?) 2.2 kernels had this, though glibc support on 32-bit platforms lagged a bit. Since I was on 32-bit platforms back then it might well have been MUCH earlier (2.0? 1.2?). ext2/ext3 has a system of "features" which can be added, both fully compatible and forward compatible flags are available so to avoid corruption on incompatible features (ext3 is a set of IIRC two options, one which says that it has a journal, one which is set when mounted and removed when umounted, this is why EXT2 only mounts *clean* EXT3 filesystems). IIRC NTFS has something not that dissimilar... The feature you are looking for is "large_size", this is set automatically when the first 2GB file is created by a kernel which supports this. I've not read the code, but the following line from the same file you quoted makes me think they stash the upper bits of the file size in dir_acl (which probably isn't used for files anyway). From include/linux/ext2_fs.h: struct ext2_inode { .... __u32 i_size; /* Size in bytes */ .... __u32 i_dir_acl; /* Directory ACL */ }; #define i_size_high i_dir_acl The 2 TB file size limit actually comes from i_blocks, Google found a patch to extend this but I don't think anyone is really that interested at the moment. There are a LARGE number of other filesystems that supports this for Linux if someone actually need this! More so, if you will also find the superblock structure, you will see that ext2 is also limited to 32bit block numbers in the volume. There are good chances that this means the volume size limit of 2TB (if "block" is really the disk sector and not a group of sectors). I have no reason to doubt the statement in Wikipedia and other places which for Linux 2.6 means 16 TB for ext3 assuming the standard 4kB block size. (It depends on block size but unpatched 2.4 and earlier has a hard limit at 2TB, not sure if this applies to all 2.4 distributions, some were heavily enhanced with some features from 2.6) http://en.wikipedia.org/wiki/Ext2 http://en.wikipedia.org/wiki/Comparison_of_file_systems |
#34
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Raid0 or Raid5 for network to disk backup (Gigabit)?
ext2/ext3 has a system of "features" which can be added
So, 4GB files for ext2 is one of these additional features? OK, thanks, will know this. *clean* EXT3 filesystems). IIRC NTFS has something not that dissimilar... NTFS is more like ReiserFS. From what I've read on ReiserFS design - it is just plain remake based on the same ideas as NTFS - attribute streams, B-tree directories, MFT etc. NTFS just predates ReiserFS by around 10 years, which is a clear sign of "substandard technologies used by MS" :-) The only competitors to NTFS that time of 1993 were VMS's filesystem and Veritas's product for Solaris. (It depends on block size but unpatched 2.4 and earlier has a hard limit at 2TB So, I'm not this wrong. 2TB limit was there very small time ago. -- Maxim Shatskih, Windows DDK MVP StorageCraft Corporation http://www.storagecraft.com |
#35
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Raid0 or Raid5 for network to disk backup (Gigabit)?
Maxim S. Shatskih wrote:
.... From what I've read on ReiserFS design - it is just plain remake based on the same ideas as NTFS Then you haven't read nearly enough to have a clue. - bill |
#36
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Raid0 or Raid5 for network to disk backup (Gigabit)?
In comp.sys.ibm.pc.hardware.storage Maxim S. Shatskih wrote:
I wouldn't know. Linux ext2/3 has a 2TB file size limit. Sorry. See the cite from include/linux/ext2_fs.h below and "__u32 i_size;" in it. ext2's limit is 4GB. I remember ext3 being compatible with ext2 in on-disk structures in everything except the transaction log, so, looks like ext3 is also limited to 4GB per file. Well, yes, if you use a pretty old kernel. Or turn large file support off. Standard limit is 2TB at the moment. And you don't need to quote kernel source at me, I happen to have files 4G on ext2 at this moment. The inode type has been extended some time ago. An overview over the current limits of ext2 is, e.g., he http://en.wikipedia.org/wiki/Ext2 One thing you need to do in your software for it to be able to handle the large files is to define #define _FILE_OFFSET_BITS 64 in order for all the relevant types to be 64 bits transparently. Note that you need the functions using ''off_t'' for position specification. More so, if you will also find the superblock structure, you will see that ext2 is also limited to 32bit block numbers in the volume. There are good chances that this means the volume size limit of 2TB (if "block" is really the disk sector and not a group of sectors). Filesystem size currently is 16TB. But you need large block device support enabled in the kernel to use that. I think that is not yet the default. Arno |
#37
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Raid0 or Raid5 for network to disk backup (Gigabit)?
In comp.sys.ibm.pc.hardware.storage Maxim S. Shatskih wrote:
ext2/ext3 has a system of "features" which can be added So, 4GB files for ext2 is one of these additional features? OK, thanks, will know this. *clean* EXT3 filesystems). IIRC NTFS has something not that dissimilar... NTFS is more like ReiserFS. From what I've read on ReiserFS design - it is just plain remake based on the same ideas as NTFS - attribute streams, B-tree directories, MFT etc. NTFS just predates ReiserFS by around 10 years, which is a clear sign of "substandard technologies used by MS" :-) The only competitors to NTFS that time of 1993 were VMS's filesystem and Veritas's product for Solaris. (It depends on block size but unpatched 2.4 and earlier has a hard limit at 2TB So, I'm not this wrong. 2TB limit was there very small time ago. Well, the 2.6.0 was published in december 2003. I would not call 4 years ''very small time'', considering disk sizes in 2003. There are, BTW, some more filesystems available under Linux and they are basically all pretty compatible. For really large filesystems you would probably not use ext2 anyways, but perhaps XFS (which also has been available on Linux since around 2001). XFS has a file size limit and filesystem limit of 8 exabytes. Arno |
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