Questions about hard disks' performance, issues, tips, and software.

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8
votes
2answers
4k views

High disk I/O when cache is used?

A few days ago I noticed a disk I/O wait and disk activity drop (which was great). Then I also notice that my cache was full(*) and fragmented. Then I flushed cache. After that, disk latency and disk ...
8
votes
2answers
20k views

How can i check remaining disk quota?

df does only report the disk free space, how can i get my allowed free space ?
8
votes
5answers
6k views

OSX - Full Disk Encryption [closed]

What options are available for OSX full disk encryption? Which of them is the best?
8
votes
3answers
654 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 ...
8
votes
3answers
9k views

Best Nagios plugin for SMARTd / smartmontools?

I've installed SMARTd / smartmontools on a server and I want to monitor it over Nagios. However on Monitoring Exchange, I see several plugins ...
8
votes
7answers
12k views

Multiple USB backup targets with Windows Server Backup

I'm trying to add multiple USB external disk targets to a Windows Server 2012 Backup schedule. Having gone through the steps in the GUI to add an additional target, the process fails with the error ...
8
votes
1answer
2k views

Recover data from SCSI hard disk

We've got an old server with SCSI hard disk. The server crashed last week and it isn't exactly known what hardware component is damaged. Since the server is due to be retired anyway we don't want to ...
8
votes
5answers
5k views

Partial-stroking / Short-stroking / Half-stroking Hard Drives?

Could anyone here explain to me what is implied by this term? (I've seen the same thing mentioned with the 3 terms). At first when I read about it, for some reason I understood that it was some way ...
8
votes
2answers
402 views

Are there any notable advantages (or disadvantages) to using EFI firmware and GPT boot disks in an ESXi environment?

My basic question is, as the title asks: are there any notable advantages (or disadvantages) to using EFI firmware and GPT boot disks in an ESXi environment? By "notable," I mean anything other than ...
7
votes
9answers
5k views

Linux: How to find out whether the harddrive is causing a bottleneck?

I'm not asking how to find out where a bottleneck is. I just what to know how to check if the harddrive is being used at its limit (and hence causing a bottleneck). Something like top where I can see ...
7
votes
3answers
16k views

How is disk speed measured and what is fast? How long should a copy of 1500 GB take?

How is disk speed measured? Is it Mbit or Mbyte per second read? What is average today and what is fast and what is very fast in the industry? Let's say somebody says it takes a long time to make a ...
7
votes
4answers
19k views

What do these disk errors in syslog mean?

I just rebooted my monitoring server for the first time in a while, and the following starting filling the screen: Jul 11 23:52:30 monit kernel: [ 25.255908] ata1.00: exception Emask 0x0 SAct 0x0 ...
7
votes
5answers
9k views

SAS or SATA for 3 TB drives?

We are looking to purchase new 3 TB enterprise-grade drives and can buy either SAS or SATA models. AFAIK, SAS generally gives better performance than SATA, but searching for benchmarks I found ...
7
votes
4answers
428 views

Purchasing hard drives with non-sequential serial numbers

I've always heard that you should not purchase hard disks with sequential serial numbers for any storage system. Now I find myself, for the first time, in a position where I need to purchase around ...
7
votes
6answers
4k views

What causes hard disk failures?

What causes hard disk failures in general. I would like to know the common causes and how to prevent such incidence.
7
votes
3answers
7k views

How do I configure Ubuntu Server to power down drives when not used? [closed]

I just got home file server, and it contains 7 hard drives. I installed on it Ubuntu Server (Jaunty). What should I do to make it power down drives when they are not in use (most of the time they will ...
7
votes
7answers
3k views

Which file system to use for portable hard drive shared among different operating systems?

Something similar has been asked already but my criteria is a little different. I need to share a portable hard drive (USB/Firewire) between Mac OSX, Linux and Windows XP systems where the files being ...
7
votes
2answers
3k 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 ...
7
votes
2answers
313 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
8k 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
3answers
909 views

Chkdsk capabilities

I've used several different tools for repairing disks and have been wondering if there is a list of what exactly CHKDSK can repair? The MFT? Boot sector? Backup boot sector? Clusters? What common ...
7
votes
3answers
379 views

Hard disk write-once mode on Windows

Is it possible to force a hard disk into 'write-once' mode in Windows? I want to securely store logs so they can't be changed, but I can't use tapes or optical media due to performance reasons.
7
votes
2answers
13k 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
24k 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
193 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
3k views

Poor Linux software RAID 5 performance with NCQ

While salvaging a 2-disk failure in my 3-disk RAID 5 setup, I happened to notice reconstruction was faster with NCQ disabled (~90M/sec) than with the NCQ enabled (~50M/sec). Running bonnie++ to ...
7
votes
1answer
139 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
11answers
1k views

A way to finish off a dying hard drive so it can be sent in for “repair”

I have a 500G SATA hard drive in my machine that all the sudden started giving me I/O errors, until Linux simply disconnects the drive. Reboot, and then it works for a random period before failing ...
6
votes
5answers
41k views

Mount network drive as physical drive

Is there a way to mount a network location so that it appears as a local physical disk? e.g. \\computer\share as D: (not a network drive)
6
votes
3answers
574 views

Is disk serial readable from supermicro chassis?

We are working with a hosting company for managing our dedicated servers. We asked for a replacement disk on one of the servers by providing the serial number. They took out 2 other disks instead and ...
6
votes
7answers
1k views

Laptops - RAM vs Disk for performance

In the perfect world I could get everything I want, however budgets for new laptops are low so I normally can get a user a laptop + additional RAM (to at least 4Gb). This has been mostly motivated by ...
6
votes
4answers
16k 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 ...
6
votes
2answers
22k views

How do I mount sub-directory to a hard drive in Linux?

Let us assume that I have two hard drives (A,B) and have the following directories: /var/www /var/www/upload Currently if I upload a file to /var/www OR /var/www/upload ; it will be saved in drive ...
6
votes
5answers
583 views

Why do they use laptop form factor HDD's for storage servers?

The storage servers I've seen generally use 2.5" drives instead of 3.5" drives. In my experience the larger drives have better capacity, speed, and durability. Why are the smaller ones favored in ...
6
votes
4answers
6k views

Disable Caviar Green drives spinning down

A few months ago I build a 1u server to go into a colo facility. Not knowing any better, I used WD Caviar Green drives. My users have been complaining that the system can be a little slow off the ...
6
votes
7answers
16k views

Disk usage per user in Linux / Unix

I need to find out how much disk space is being occupied by each user on the network. I am aware of df and du commands: I could list the entire filesystem and AWK the output, but I wonder if there is ...
6
votes
5answers
3k views

SW SSD Raid 1 over HW RAID 10

A provider(data center) recommended I go with 1TB SSDs in a software RAID 1 over HW RAID 10 with mechanical drives. Their quote: Typically SSDs are most reliable than RAID cards and since you ...
6
votes
2answers
440 views

Could SpinRite possibly be messing up my laptop hard drives?

Context: We have a midsize business with a few dozen laptops. Whenever we get one in because someone leaves or gets an upgrade, standard procedure is to zero and then run SpinRite (level 4) on the ...
6
votes
3answers
387 views

Why Do Hard Drives Fail?

I'm just quite interested in the reasons why hard drive failures occur. Some people say that it's because it was handled poorly during the shipping and transportation processes while others say that ...
6
votes
2answers
6k views

I used “dd” to clone a drive to a larger drive. How can I leverage the additional space (linux)?

Fdisk can't see extra space I upgraded my trusty 74gb Raptor hard drive to a 600gb Velociraptor behemoth. I used "dd" to clone the drive, (i.e. "dd if=old-drive-device of="new-drive-device), swapped ...
6
votes
5answers
5k 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
4answers
2k 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
5answers
7k views

Make a hard disk sleep and only wake up when needed

I want to connect another hard disk to my computer, which I want to sleep 99% of the time. I will only use it for a few things, but I need it to be mounted at all times. To achieve this I would like ...
6
votes
2answers
672 views

Determine if C drive has 2 GB of free disk space

I am trying to determine if a target pc has atleast 2 GB of free space. Here is what I have so far: @echo off for /f "usebackq delims== tokens=2" %%x in (`wmic logicaldisk where "DeviceID='C:'" get ...
6
votes
1answer
1k 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 ...
6
votes
2answers
4k 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
473 views

mdadm: Replacing array with entirely new drives

I have a server with three 500GB drives, with most of my data in a RAID5 configuration spanning the three of them. I just purchased and installed four 1TB drives, and the intention is to move off of ...
6
votes
4answers
205 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
2answers
3k views

How do you disable the “last accessed” attribute on NTFS/Windows?

Inspired by this answer, I realize I have no idea how to disable the last accessed attribute in Windows to increase performance. If you can, how? I know in Linux you can mount the partition with the ...
6
votes
3answers
1k views

Server System drive on a USB stick? Good? Bad?

This is a follow up to this question. I am assembling a storage server with 14 SATA drives. I don't want to "waste" a drive for the OS system, so I thought I could isntall and run the OS from a USB ...