In computing, file system fragmentation, sometimes called file system aging, is the inability of a file system to lay out related data sequentially (contiguously), an inherent phenomenon in storage-backed file systems that allow in-place modification of their contents. File system fragmentation ...
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48 views
Rebuilt nonclustered indexes quickly get fragmented again
I've got a couple of nonclustered indexes on tables that have rows inserted quite often. These indexes are currently around 90% fragmented, according to SQL Server. If I rebuild them, they go down to ...
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45 views
Can someone give me advice on these rules to prevent DDOS where fragmented packets are sent without the initial SYN fragment ?
iptables -N NEW_TCP_PACKETS_NO_SYN
iptables -A INPUT NEW_TCP_PACKETS_NO_SYN -p tcp ! --syn -m state --state NEW -m limit --limit 10/day -j LOG --log-prefix "New packets but not syn:"
iptables ...
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2answers
120 views
Mysql 5.5 Defragmentation not reducing the fragmentation percent
We are running OPTIMIZE TABLE , but not seeing any fragmentation reduction. They are as high as 120% to 200%.
Am calculating the fragmentation % using this: Data_Free / (Data_Length + Index_Length)
...
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133 views
Scientific data storage: many small files, one volume or several?
I have about 8 TB worth of 'sample' data with the following characteristics:
each sample: 5-15 GB in one folder containing ~20k files and ~10k subfolders (2000 top-level, 5 sub-level containing a ...
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3answers
104 views
Rebuilding the Management Studio Index in SQL Server 2005
Does anyone know if using the SQL Server Management Studio Index Rebuild, rebuilds the index online or offline?
Reading the help documentation doesn't say anything on this (so I would assume it is ...
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59 views
Fragmented packets on Red Hat Linux
Our application runs on Red Hat Linux 8.0 3.2-7, Linux kernel version 2.4.32.
We've found that the OS does not know how to handle fragmented packets. When receiving a large amount of fragmented ...
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128 views
Database fragmentation with PostgreSQL 8.1
I'v got a 220M db running under PgSQL 8.1 (upgrade not possible ATM.).
If I do a reindex, the db size goes to 220 but then it starts growing over time (it shoudln't), a few megs per day.
I did ...
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1answer
317 views
Is there a way of setting an MTU lower for traffic destined to a specific IP address on Cisco ASA?
I have a number of VPN sites where the MTU is lower than standard (1500). I have had at least one site where fragmentation of packets has had an effect on the success of building an IPSEC tunnel.
...
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1answer
108 views
(RFC-791) Application Layer PDU size, guaranteed to pass without fragmentation
I am writing a client-server python application, a part of which is using UDP Multicast to communicate. And my current concern is about fragmentation.
RFC 791 (page 24) says:
Every internet ...
6
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2answers
146 views
Can a tmpfs become fragmented?
Since a tmpfs exists only in memory, can it become fragmented like memory can? Are there mechanisms to automatically defragment the memory, and thus increase - even slightly - the access speed of ...
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3answers
726 views
What might prevent IKE handshake success in building an IPSEC tunnel?
We use Cisco ASA for our IPSEC VPNs, using the EZVPN method. From time to time we encounter problems where an ISP has made a change to their network and our VPN stops working. Nine times out of ten ...
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4answers
145 views
How accurate are Diskeeper's claims that fragmentation causes crashes, aborted bootups and other mayhem?
A white paper published by Diskeeper Corporation states at page 3 that,
The most common problems caused by file fragmentation are:
a) Crashes and system hangs/freezes
b) Slow boot up and ...
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123 views
how to do fragmentation attack via ubuntu machine
I wish to test my system which has snort installed on it.
I want to do fragmentation attack such as tiny fragment attack and wish that it should be logged by snort.
any suggestions? any graphical ...
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1answer
186 views
Index fragmentation and reorganizing database pages
Say you have a database with heavy index fragmentation. Say this database also has a lot of free space due to frequent deletes in its data file. This free space is not contiguous.
If I rebuild all ...
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2answers
298 views
How can Windows defragmentation tools cause internal fragmentation in SQL Server?
I was just reading this article where the author talks about the file system fragmentation that can be caused by growing database files. There was one bit that I didn't quite follow.
What about ...
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1answer
121 views
IPv4 Fragmentation over ethernet
I was under the assumption that fragmentation only happens at the router however this makes me wonder how datagrams get to the router without first being fragmented at the source to comply with the ...
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3answers
1k views
NETAPP Fragmentation
We all know that once a disk (or storage system for that matter) gets introduced into use, the performance degrades due to fragmentation of files. This seems to be why disk defragmentors are in ...
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4answers
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Does Windows Defrag utility reports fragmentation correctly on a RAID system?
We have a server with a RAID volume. Windows DEFRAG shows very high fragmentation (90%) on the volume. My chief asked if DEFRAG reported fragmentation is correct (or near correct) or not.
We don't ...
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2answers
444 views
What is the equivalent of Cisco's 'ip virtual-reassembly' for a Juniper ISG 2000
I tested my dns servers with the oarc test and my size limit is at least 1403 bytes. I performed the same test before my Juniper ISG 2000 and the result is 2047 bytes.
According to the chapter IP ...
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3answers
800 views
Could MFT fragmentation be a problem on my busy file server?
Windows Server 2003 SP2
LUN mounted from SAN
Millions of small files across hundreds of thousands of directories (100GB total)
NTFS with 4k cluster size
While doing the initial file crawl for backups ...
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2answers
219 views
Why can't I rebuild some SQL Server indices?
I've got a table in my SQL Server 2005 database with two indices that are heavily fragmented (33.3% and 85.7%). The table looks like the following:
CREATE TABLE [dbo].[Seasons](
[SeasonID] ...
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460 views
How is Win32_DefragAnalysis FilePercentFragmentation Calculated
SCOM 2007 R2 added a fragmentation analsysis health check that is producing warnings on many of my servers. To try to understand how SCOM is determines the fragmentation level, I created the following ...
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103 views
Is there a way to determine fragmentation statistics about a single file on Win2003?
Basically, I don't care about fragmentation on the disk as a whole, I'm just curious about one file in particular... in my case, a SQL database and transaction log file. I'm looking for something ...
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2answers
620 views
How can I deliberately fragment specific files? (NTFS)
This may have been asked but...
I'm trying to profile the impact of file fragmentation on one of our business applications. What's the easiest and cleanest way to cause a 20GB file to fragment into ...
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8answers
1k views
Swap file fragmentation: fact or fiction?
This is about Windows, but I'm sure it applies to other OS as well.
I've heard people say that if you want better performance, you should avoid swap file fragmentation. To do this, you can either ...
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367 views
FTP Client upload: preallocate file before starting the transfer
I'd like to limit server disk fragmentation when multiple clients upload to an FTP server simultaneously.
Is there a way to tell FTP server to preallocate disk space for a big block of an incoming ...
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4k views
SQL Database physical file fragmentation
I know that there are really three kinds of fragmentation that I need to be concerned about as a DBA:
Index Fragmentation in the SQL data files, including clustered index (table) fragmentation. ...
