Disk storage is generally the permanent data storage of a server.

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41
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6answers
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How can I successfully mount an 8-bit SCSI drive on a modern computer?

I have a number of internal 8-bit SCSI-1 drives that I'd like to archive for historical purposes. These are all the old NeXT Cubes and NeXTStations (monochrome and color) that were used by id ...
27
votes
2answers
5k views

Why are enterprise SAS disk enclosures seemingly so expensive?

I will begin by stating that I do not believe this is a duplicate of Why is business-class storage so expensive?. My question is specifically about SAS drive enclosures, and justifying their expense. ...
20
votes
1answer
241 views

Is it possible that just one bit switches so my file shows me a letter “Q” instead of a “S”

In our application we use Hibernate and PostgreSQL to store data. In one of our database tables we have a discriminator column which says for example "TIPPSPIEL". It is a fixed string and can not be ...
19
votes
4answers
1k views

Why would a heavily disk intensive application run faster on a SAN than on a Physical Disk?

Why would a heavily disk intensive application run faster on a SAN than on a Physical Disk? I would have expected the Physical disk to be slightly faster but in fact the process ran 100 times faster ...
19
votes
6answers
6k views

Is a hard drive's serial number globally unique?

On Linux I can use smartctl to get a hard drive's vendor, model, firmware revision and serial number: # smartctl -a /dev/sdb smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build) ...
18
votes
2answers
401 views

An unknown tool is wiping our Virtual Machines and we can't ID it

A console view of a Windows 2008 R2 VM, on vSphere is showing the following screen: "Operation 2 of 2" "Wiping disk" Can someone advise on what this program is? Some information on this mystery: ...
17
votes
3answers
12k views

limit linux background flush (dirty pages)

Background flushing in linux happens when either too much written data is pending (adjustable via /proc/sys/vm/dirty_background_ratio) or a timeout for pending writes is reached ...
16
votes
8answers
1k views

Optimal UNIX File System Partition + Setup Strategy

When partitioning a new system disk(s) for UNIX, what is your prefered strategy for both desktop and/or servers? Please include disk partition layout, file system format(s) and options, mount points, ...
15
votes
1answer
1k views

In Linux, why isn't superuser root's folder under /home?

You can create a user that has privileges like root, and it's home directory will fall under /home/username. Why does root get its own folder at the top level of the file system? Is this just ...
15
votes
3answers
23k views

Setting Low Disk Space Alerts on Windows Server 2008

I was wondering if there is an easy way to trigger an e-mail alert on Windows Server 2008 when any logical disk partitions become low on space. I have 2 SQL servers that have come close to running ...
14
votes
4answers
59k views

Is it possible to mount/unmount a physical hard drive in Windows XP?

Is it possible to mount/unmount a physical hard drive in Windows XP? Ideally, I'd like to be able to do this from the command line so that I could have batch files to do it, ie: mount.cmd unmount.cmd ...
13
votes
6answers
8k views

SATA Disks that handle write caching properly?

It's pretty common to see advice to disable the write cache on individual disks used for databases because otherwise some disks will acknowledge writes that haven't yet made it to the disk surface. ...
12
votes
7answers
662 views

How do storage IOPS change in response to disk capacity?

All other things being equal, how would a storage array's IOPS performance change if one used larger disks. For example, take an array with 10 X 100GB disks. Measure IOPS for sequential 256kb block ...
12
votes
2answers
479 views

df vs du. Is my disk really full?

Strange problem... Why i have full / partition used, but it's not really used? Fast info: xwing ~ # df -h Filesystem Size Used Avail Use% Mounted on rootfs 16G 15G 75M 100% / ...
12
votes
2answers
3k views

CentOS thinks Disk is busy, can't mount or fsck

I'm a longtime user, and first time question submitter. I've spent a full day searching this and many other sites for a solution, but I must resort to requesting assistance to resolve my situation. ...
11
votes
4answers
2k views

Available disk space on Unix/Linux OS

How to get available disk space on Unix/Linux OS, including unallocated space (which wasn't assigned to any partitions)?
10
votes
5answers
15k views

Linux - Help, I'm running out of inodes!

I have a filesystem that has lots of small files. Currently about 80% of inodes are used (I checked with df -i), however only 60% of disk space is used. How can I 'increase' the number of inodes? If ...
10
votes
3answers
2k views

Extremely Slow IO with Simple PostgreSQL 8.4.4 Queries on Centos 5.5

The strange and extremely slow IO pattern I'm seeing is this (output of iostat -dxk 1 /dev/xvdb1): Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm ...
9
votes
5answers
12k views

How do I easily repair a single unreadable block on a Linux disk?

My Linux system has started throwing SMART errors in the syslog. I tracked it down and believe the problem is a single block on the disk. How do I go about easily getting the disk to reallocate that ...
9
votes
9answers
2k views

On a modern system, will using disk compression give me better overall performance?

It seems that CPU increases have outpaced disk speed for a while. Assuming a desktop or laptop with modern dual core Intel/AMD CPU and a single average SATA disk, would doing compression on most all ...
9
votes
3answers
546 views

Slow filesystem access

I'm trying to diagnose a slow filesystem issue on a server I look after. It's been ongoing for quite some time, and I've run out of ideas as to what I can try. Here's the thick of it. The server ...
9
votes
1answer
2k views

Why is this SSD drive failing with bad sectors, and was it predictable?

Note: this question was previously closed as off-topic. You can read the discussion. My reasons for asking it here are: This drive is in an offline content cache server for schools in rural Zambia. ...
8
votes
4answers
660 views

root full Linux. No free blocks

df -h reports the '/' partition to be 100% full. While running du -hs * on each directory of this partition shows there is still lot of space. tune2efs which reports just one block to be free. Ran ...
7
votes
6answers
957 views

So what do we use instead of PartitionMagic now that Symantec's killed it? [closed]

Apparently, since the last time I had to do a lot of playing with partitions and images, Symantec acquired, neglected, and killed off PartitionMagic. (Yeah, it's been a while.) What, then, are we ...
7
votes
3answers
10k views

Linux disk IO load breakdown, by filesystem path and/or process?

Does anyone have experience with a tool that can provide an indication of disk IO load by filesystem path. I use to 'iostat' utility, frequently, to learn how much disk activity is taking place on a ...
7
votes
7answers
4k views

Equivalent of SysInternals FileMon for Linux?

I'm attempting to debug an application on Ubuntu - I need to listen to file open attempts (even for files that don't exist). Process Monitor (formerly known as FileMon) is available on Windows - ...
7
votes
2answers
292 views

Disk latency is growing since a few days ago, with no special change in disk throughput

Here is the disk latency graph of my server. The server has two 5400 RPM 32MB Cache SATA 3.0Gb/s hard drives mounted with software RAID 1 configuration. No special changes has happend in those days ...
7
votes
5answers
7k views

Linux md vs. LVM performance

I am trying to tune my NAS, running openfiler, and wondering why I'm getting relatively poor read performance from 4 WD RE3 drives in RAID 5. EDIT: Please note I am talking about the buffered disk ...
7
votes
5answers
4k views

How do I measure disk thrashing on linux?

How do I accurately observe and measure the amount of virtual memory utilization and activity on Linux? I know there is vmstat, but how do I interpret the results? Or, what is better?
7
votes
2answers
12k views

How can I connect a SAS drive to USB?

I have a Dell T710 with Seagate Cheetah 15k.7 SAS disks. If the T710 motherboard dies, I'll need to resort to one of my nightly off-site backups and salvage the journal/logfile from the SAS disk to ...
7
votes
2answers
11k views

Constant disk activity - how can I tell what files are being accessed nonstop?

On my Windows 2003 Server, the disk activity has been out of control recently - the disk queue is getting long, and I'm getting heat on the wait time for resources. I'm looking for a tool that will ...
7
votes
3answers
19k views

How do you passthrough native SATA drives to a guest on ESXi?

I have ESXi 4.0 running on an Intel DX58S0 Mothboardboard with an Intel Core i7 930 processor. VT-d is also enabled. I have three drives in the system, drive 0 is used for ESXi. Drive 1 and 2 ...
7
votes
1answer
166 views

Backup process flushes disk cache

I've got a backup process which reads quite a lot of data from disk, and therefore uses up all memory for disk cache, swapping off apps and other cached data in the process. There is no benefit to ...
7
votes
1answer
106 views

Disk size addressable by the OS

I have a 3ware 9550SXU-12 storage controller and 750G disks connected to it. The disks are configured as single units (not JBOD). I've been running some performance tests, mainly to see the impact of ...
6
votes
4answers
1k views

Server 2008 R2 requires 2 disks to boot

Weird one. I have a domain controller with Server 2008 R2. It is a hack job but is reliable. AMD system. AM2 6000+ Asus Crosshair MB. The server is utilizing 5 Sata ports for Hard disks of assorted ...
6
votes
2answers
1k views

Why are “sectors per track” still relevant on a modern OS with modern drives?

I am building out a new machine and the raid controller is asking me for sectors per track. I haven't had to deal with disk math in a long time (1998?), and I can't find anything that pertains to ...
6
votes
2answers
3k views

How long should rebuilding 250GB take? [closed]

In a PowerEdge 1900 have I a hardware RAID 5 of 5x250GB disks + 1 hot spare 250GB. Disk 2 have errors, so I forced it offline in the raid bios to replace it. Now it have been rebuilding to the hot ...
6
votes
4answers
183 views

Crashing my disk using Java

I have a Java program that must do the following 3 things: Download a file from a website. Run the file trough testA and testB (both in java) Delete the file and save the test results on the disk. ...
6
votes
4answers
3k views

Postgres DISK IO very high. What can I do to reduce it immediately?

I'm aware faster disks than what I'm using will help but this will take longer to put in and I am trying to use some emergency measures to decrease disk IO. atop is reporting DSK usage on the red ...
6
votes
3answers
369 views

How to keep subtree removal (`rm -rf`) from starving other processes for Disk I/O?

We have a very large (multi-GB) Nginx cache directory for a busy site, which we occasionally need to clear all at once. I've solved this in the past by moving the cache folder to a new path, making a ...
6
votes
1answer
125 views

How to prevent IO Load under Linux for Video serving?

I'm currently serving videos of conferences via Nginx on 3 servers; 4 cores, enough memory (no swap used) and RAID-10 with 8 drives per server. Unfortunately iostat -xd 1 gives me 100% on all 3 ...
6
votes
2answers
10k views

How can i check remaining disk quota?

df does only report the disk free space, how can i get my allowed free space ?
6
votes
4answers
228 views

Frequently accessed files and I/O usage

I'm curious, from a performance standpoint, is there an advantage in storing all files in one directory versus having each file in a separate directory? I'm not concerned about organization. Also, ...
6
votes
2answers
2k views

Hadoop disk fail, what do you do?

I would like to know about your strategies on what to do when one of the Hadoop server disk fails. Let's say, I have multiple (>15) Hadoop servers and 1 namenode, and one from 6 disks on slaves ...
6
votes
3answers
161 views

How bad is it to use a virtual file system with VMWare?

IT is running a series of VMs that we'd like to see optimized further: if the VMs' are Windows XP, storing their NTFS images out to the virtual disk (ext3) provided by Linux/VMWare, how much of a hit ...
5
votes
5answers
727 views

Linux: how many disk I/O does it take to read a file? How to minimize it?

According to this paper on Facebook's Haystack: "Because of how the NAS appliances manage directory metadata, placing thousands of files in a directory was extremely inefficient as the ...
5
votes
6answers
4k views

How can I tell what's spinning up my drive?

I have enable "spindown" on one of my Linux server's drives, which is only accessed by a BitTorrent client - meaning, when I don't have torrents running, nothing else should be accessing the disk and ...
5
votes
4answers
8k views

Howto check disk I/O utilisation per process

Im having a problem with a stalling Linux system and I have found sysstat/sar to report huge peaks in disk I/O utilization, average service time as well as average wait time at the time of the system ...
5
votes
1answer
839 views

No space left on device — but there is space

I'm running an Ubuntu 12.04.1 server in a VMware virtualized environment that has a strange issue. Twice now, at seemingly random times, the machine has suddenly been unable to write to the root ...
5
votes
3answers
1k views

Linux different size for df and du for root partition

On my CentOS server, both of the commands are showing different usage for disk / , df shows this output: Filesystem Size Used Avail Use% Mounted on /dev/xvda2 16G 14G 952M ...