Norphy Posted July 3, 2006 Posted July 3, 2006 Do you bother with it? Does it make much difference? What software do you use to do it? Cheers, Norphy
ChrisC Posted July 3, 2006 Posted July 3, 2006 On the network, no we don't, at home/standalone computers, yes,I do. I use windows defrag. It generally improves the file access time, seeing as all the little bits of file (literally) are all in the right places afterwards. Chris
DMcCoy Posted July 3, 2006 Posted July 3, 2006 Defrag only orders the files on the filesystem level, it doesn't actually put them in a specific physical location on the hard disk. It will reduce the number of requests on the filesystem level if the files are seen a sequential to the os.
Chafftech Posted July 3, 2006 Posted July 3, 2006 Defrag only orders the files on the filesystem level, it doesn't actually put them in a specific physical location on the hard disk. It will reduce the number of requests on the filesystem level if the files are seen a sequential to the os. Hmm, first I have ever heard of this. I was always under the impression that it physically moves the files. Found this on the wikipedia: Defragmentation From Wikipedia, the free encyclopedia Jump to: navigation, search In the context of administering computer systems, defragmentation (or defragging) is a process that eliminates fragmentation in file systems. It does this by physically reorganizing the contents of the disk in order to store the pieces of each file close together and in order (contiguously). It also attempts to create large regions of free space using compaction, to impede the return of fragmentation.
DMcCoy Posted July 3, 2006 Posted July 3, 2006 These are posts from one of the developers of Raxco Perfect disk Please remember that all defraggers work at the LOGICAL level - NOT the PHYSICAL level. The LOGICAL level is the file system view and the PHYSICAL level being at the sector level. If a file is LOGICALLY contigous, then only 1 request needs to be made to access the file. If a file is LOGICALLY fragmented, then multiple requests need to be made to access the file. The performance gain is the "difference" between performing 1 request vs multiple requests. Even if a file is LOGICALLY contiguous, there is no guarantee that it is PHYSICALLY contiguous. Please see my rather crude diagram below that attempts to visually show this difference. Another point to remember is that the defrag APIs require that all file moves be done in multiples of X clusters. Under NT4, X is 16 clusters. Under Win2k, it is derived from the page size and is either 8, 4, or 1 clusters. Appplications/Defraggers | Operating System | File System (logical view) ------------------------------------ (physical view) | Hard Drive Controller | Hard Drive While defragging takes place at the logical level, when you "move" a file, it does translate into things happening at the physical level. However, there's not a good way to know what is going on as it is the hard drive controller that is doing the logical to physical translation. The HDD controller translates the logical requests to physical requests and directs the read/write heads to "do their thing". Even if a file is logically contiguous, there is no guarantee that it is physically contiguous and vice versa.
kingswood Posted July 3, 2006 Posted July 3, 2006 Defragging will prolong the life of your nice shiny SCSI hard drives on your server. Trust me- not defragging your server will have more of a negative effect than just causing pretty red blocks in your analysis screen!
SpuffMonkey Posted July 3, 2006 Posted July 3, 2006 In the olden days (about 20 years ago) when I was doing big databases - we actually used to try and split the data up across the disk using some sort of normalised curve, because the slowest bit of accessing a file was the physical seek on the disk, so some genius had worked out the optimal spread of data across a disk to get the fastest continuous read of data. It used to knocka few milliseconds off.
tosca925 Posted July 3, 2006 Posted July 3, 2006 I defrag all our server drives once a year, normally in the 6 weeks holiday. If no one is in i log in from home and set them all off.
contink Posted January 15, 2008 Posted January 15, 2008 Reviving this topic somewhat but only to give folks a heads up. Having use O&O defrag in the past and more recently (last 3 years) Diskeeper Pro I've been keeping my eye out for a decent server defragmenting util that didn't cost the earth just because it's on a server OS until today.. Raxco PerfectDisk have their server version at $99 at present and if you have any licenses from their competitors, even just workstation licenses you can apply for a 20% discount via their trade-up form. .. but it actually gets better because they then send you an email which offers you a one day only 35% discount on all their PerfectDisk products (including the server, and exchange products). I decided to give it a go at home as my home server has suffered from a lack of consistent defrag for quite a while now and at less than £35 for a server license I figure it's a chance to test drive something for school... Anyways, thought I'd share that nugget as it caught me unawares.
pete Posted January 16, 2008 Posted January 16, 2008 I set our servers to defrag system and application partitions at the weekend after (typically one drive on Saturday, one on Sunday). Data partitions are defragged monthly*, after the end-of-month backup. *mainly because it's really handy to have a shadow copy of the file someone just deleted when the tape is off-site.
bizzel Posted January 16, 2008 Posted January 16, 2008 Once a month as a scheduled task. Happens over the weekend but only defrags C and the user areas.
cookie_monster Posted January 16, 2008 Posted January 16, 2008 (edited) Same here i defrag the system partition each weekend and the data partitions once a month at the weekend, as it's performed more frequently it only takes a few mins rather than leaving it untill it takes several hours. I found once i started this that performance seemed to pick up it's difficult to tell now i do it every week but the first time i ran a defrag there was a noticable improvement. On a sidenote are you sure that the Raxco Perfect disk comment is not refering to RAID/SAN/NAS devices as the physical layer which is represented as a logical drive to windows. This means that unnecessary calls are generated to the RAID controller if the logical table is fragmented. Is this the same with a standard IDE/SATA single disk though? Edited January 16, 2008 by cookie_monster
DMcCoy Posted January 16, 2008 Posted January 16, 2008 Same here i defrag the system partition each weekend and the data partitions once a month at the weekend, as it's performed more frequently it only takes a few mins rather than leaving it untill it takes several hours. I found once i started this that performance seemed to pick up it's difficult to tell now i do it every week but the first time i ran a defrag there was a noticable improvement. On a sidenote are you sure that the Raxco Perfect disk comment is not refering to RAID/SAN/NAS devices as the physical layer which is represented as a logical drive to windows. This means that unnecessary calls are generated to the RAID controller if the logical table is fragmented. Is this the same with a standard IDE/SATA single disk though? I believe this applies to all modern drives. It will still reduce the number of logical disk access requests to the filesystem, but only the disk controller knows where the sectors are physically located.
techyphil Posted April 2, 2008 Posted April 2, 2008 Someone mentioned before that defragging may actually do more damage if used on a data partition thats on a set of SCSI Raid Disks (which mine are). Ive got 4HDDS in Raid 5 cfg that I want to defrag but want to make sure that it works for you guys at the moment. Cheers
button_ripple Posted April 2, 2008 Posted April 2, 2008 i defrag the servers once a week because staff are always moving there files around and at the minute we are loading lots of software to the network. Defragmentation is important if you regularly access lots of files on your computers hard drive. it does physically move files on your hard drive as it will attempt to place them as close together as possible so that it hasn't got to go to the end of your disc to find one file. It doesn't affect files as you see them - this is what scares most people they think that there files are going to go missing because it is going to cut and paste them somewhere else.
Dafty Posted April 2, 2008 Posted April 2, 2008 I must admit that I never defrag our servers. But from reading this I may consider doing it this weekend. The only thing I am really concerned about is the the safety of the data.
DMcCoy Posted April 2, 2008 Posted April 2, 2008 Not directly related, but do read it if you want to know a little more about whats going on. http://www.raxco.fi/doc_images/pd_raid.pdf "At the core of this issue is the common perception that disk defragmentation software directly shuffles around disk clusters. That belief is incorrect."
Dafty Posted April 2, 2008 Posted April 2, 2008 Thanks for the info DMcCoy! Just out of pure curiosity: What is the general consensus on defragging servers?
DMcCoy Posted April 2, 2008 Posted April 2, 2008 Thanks for the info DMcCoy! Just out of pure curiosity: What is the general consensus on defragging servers? I still do it, it does reduce the logical requests needed for a file. I just don't defrag that often. It's just not some magic performance or instability cure that it's made out to be Data loss isn't really an issue, nor is disk life (it's not really going to increase or decrease the life span - unless you run it all the time which might increase the disk wear a tiny bit).
enjay Posted April 2, 2008 Posted April 2, 2008 Those of you who are doing this as a scheduled task, can I ask what command you're using for a Win2K server.
zag Posted April 2, 2008 Posted April 2, 2008 Defragging mine now No need to do it more than 3 monthly in my opinion. 90% of our files are static and haven't moved in years. I suspect its the same in most schools.
enjay Posted April 2, 2008 Posted April 2, 2008 No need to do it more than 3 monthly in my opinion. 90% of our files are static and haven't moved in years. I suspect its the same in most schools. Depends on the drive, surely - the drive which houses the users' areas is changing almost constantly.
cookie_monster Posted April 2, 2008 Posted April 2, 2008 I schedule ours to run once a month on the servers with user folders and shared areas, i didn't do it in the past and the defragmenter showed the volume as very defragmented when i started doing it. As far as i'm concerned it improves performance and if you do it often it only takes a few mins rather than hours. Well it can take longer on very large storage but on one of our servers 100Gb is done in about 30 mins.
button_ripple Posted April 2, 2008 Posted April 2, 2008 Well it can take longer on very large storage but on one of our servers 100Gb is done in about 30 mins. 2 x 500 GB Hard drives about 75-80% full take 15 mins here!!
cookie_monster Posted April 2, 2008 Posted April 2, 2008 Yep the more often you run it the less time it takes. This server is very heavily used for lots of files and it a bit on the tired side as well.
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