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Questions tagged [fragmentation]

File system fragmentation 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.

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 increases disk head movement or seeks, which are known to hinder throughput.

Source: wikipedia

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Linux memory fragmentation

Is there a way to detect memory fragmentation on Linux? This is because on some long running servers I have noticed performance degradation and only after I restart process I see better performance. I noticed it more when using Linux huge page…
Raghu
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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. Identify this using DBCC SHOWCONTIG (in SQL 2000) or…
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Cause of page fragmentation on "large" server with xfs, 20 disks and Ceph

Any insight from someone with a bit of experience in the linux IO system would be helpful. Here is my story: Recently brought up a cluster of six Dell PowerEdge rx720xds to serve files via Ceph. These machines have 24 cores over two sockets with two…
pingu
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How to use MSSQL, rebuild all indexes on all tables? MSSQL Server 2008

I have a mssql database, we'll call it: mssqlDB01. I've been tasked with performing defragmentation on all of the tables. This database has a few hundred tables and each table has a range of 1 to 15 indexes per table. Google led me to discover a…
parsecpython
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How to handle Redis raising memory fragmentation?

I have a Redis 3.0.5 instance that tend to show growing mem_fragmentation_ratio over time. The application using that instance is constantly creating and deleting keys. After one month, I end up with a mem_fragmentation_ratio > 1.30. This impacts…
Olivier Dauby
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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 manually specify a constant size for the swap file,…
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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 stored files?
Laurent Pireyn
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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 have any defrag being made for a long time (at…
Fabricio Araujo
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How does Windows Storage Space deal with partition fragmentation? Will this cause performance issues?

I'm using Windows Storage Space with multiple hard drives. If I create multiple virtual disks, then delete some of them, and resize some of them, will the virtual disk be finally divided into multiple fragments and will these fragments be located…
Shiyao Wang
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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 "Fragments Filtered" and this article, I think I…
2xyo
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ADSL router happily accepts IPv6 packets of 2K in size

As I understand IPv6 fragmentation, the routers do not perform fragmentation, only the end-to-end nodes do. And when any router along the path receives a packet larger than the MTU of the link to its next hop, it'll discard it and reply to the…
Mansour
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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. I am able to set the MTU on the equipment at the…
dunxd
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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 the ISP denies that their change could have…
dunxd
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fragmentation leads to excessive vhdx backup size

The server hosts a service called MultiCash-Datenbank. For each user it keeps two cache files (SPASD32.SRC and SPASD32Z.SRC), which grow in size by ~1MB/day. There's also a bunch of small data files added each day. I have been observing our…
theultramage
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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 roughly (say) 35,000 pieces? Ideally the…
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