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

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6
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3answers
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Which is better, Split or Monolithic VMware disk in a production enviroment?

Ok, so I have read a bunch of material on-line and curious as to your thoughts on split vs monolithic disk in a production environment. We are going to be building the VM server on a server that has ...
6
votes
4answers
243 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
171 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 ...
6
votes
2answers
3k views

How to determine which file/inode occupies a given sector

I received messages in /var/log/kern.log that indicate drive failure. The messages occured while copying my $HOME between drives (ext4 -> ext3): [ 5733.186033] sd 4:0:0:0: [sdb] Unhandled sense code ...
6
votes
4answers
1k views

My linux server takes more than an hour to boot. Suggestions?

I am building a CentOS 5.4 system that boots off a compact flash card using a card reader that emulates an IDE drive. It literally takes about an hour to boot. The ultra-slow part occurs when Grub ...
6
votes
3answers
9k views

hdparm on OS X

On Linux, I can verify and change the low level parameters of my disk drive using hdparm. Is there an utility providing the same capabilities for OS X, or perhaps some other way of manipulating the ...
6
votes
2answers
5k views

Relation between disk IOPS and sar tps

I'm trying to estimate IOPS requirements of my application running on 32-bit CentOS 6.2. I started to take some measurement on a machine with SATA disks and I'm quite confused of difference between ...
6
votes
2answers
6k views

Dell PERC 4 (PowerEdge 2850): Unresolved configuration mismatch between disks(s) and NVRAM

We had an extended power outage (almost four hours); now I have a Dell PowerEdge 2850 server which is giving me this error (from a PERC 4e/DI) on boot up: All drives are listed in the PERC ...
6
votes
9answers
2k views

2 drives, slow software RAID1 (md)

I've got a server from hetzner.de (EQ4) with 2* SAMSUNG HD753LJ drives (750G 32MB cache). OS is CentOS 5 (x86_64). Drives are combined together into two RAID1 partitions: /dev/md0 which is 512MB ...
6
votes
4answers
7k views

3.5“ 15k RPM drives vs 2.5” 10k RPM drives

How do 2.5" 10k RPM SAS drives perform compared to 3.5" 15k RPM SAS drives? Specific areas of comparison: Random write Random read Sequential write Sequential read
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votes
6answers
5k views

Use of 2.5" Laptop Drives in a Server?

We're acquiring several 1U servers with (8) 2.5" drive slots. Although we can use either SATA or SAS, there is a large price variance as soon as you order 16 or 24 of these drives, so we are looking ...
5
votes
6answers
37k 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) Edit: Hey guys, does anyone have a solution to this?
5
votes
7answers
22k views

how to use a disk with high reallocated sector count?

After 3 years in 24x7 service a 1TB Seagate Barracuda ES.2 enterprise drive is showing signs of failure. S.M.A.R.T. reallocated sector count is high. Wikipedia article suggests that the drive can ...
5
votes
7answers
542 views

Windows drive letters A: and B:

This is a question that just popped into my mind and I can't help but wonder why it's still common for a Windows installation to be installed on C: with all other drive letters going up from D: to Z:. ...
5
votes
4answers
11k views

Performance differences between 2.5“ vs. 3.5” SAS

What real performance gains/losses are there on 2.5" vs. 3.5" 15k SAS drives. Are folks really seeing seek differences, &c?
5
votes
5answers
838 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
4answers
5k views

Maximum safe hard drive temperature?

I have two new-ish 1TB hard drives in my server, both running at 38 degrees C at the moment. Should I be worried?
5
votes
2answers
4k views

RAID 5 with big SATA disks. Do or don't?

Is it sane to build a machine with RAID 5 expecting to hold around 5 Tb (and able to grow) with 1.5 or 2 Tb SATA II disks? It will be used as audio and documents storage. I already have chosen a ...
5
votes
8answers
9k views

Can you use your own drives on Dell PowerVault MD3000i?

I would like to use my own drives in the Dell PowerVault MD3000i. Does anyone know if you are able to? We are looking at different SANs for our VM farm and would rather be able to replace a drive in ...
5
votes
6answers
5k 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
14k 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
8answers
7k views

Hard Drive Speed: RPM vs. Cache

When trying to choose a SATA magnetic hard drive (not SSD) for high performance for both random and linear access, which should be the primary factor? For example: would a 10k RPM drive with 16MB ...
5
votes
3answers
2k views

Problem with slow hard disk

We bought some new PCs in my company with the new iCore 7 and 8GB memory and the following hard disk: WESTERN DIGITAL WD8000AARS 800GB CAVIAR GREEN SATA2 The problem we have is that after installing ...
5
votes
6answers
241 views

In a managed environment, should user PCs have local external HD backups?

Our environment manages thousands of user PCs, provides high-end secure file servers. Users (from new staff to executive-level) are urged to store data to the file servers and generally do so. PCs ...
5
votes
1answer
3k views

Can I get the model information for my hard drives with a command in Linux?

Is there a Linux command that would allow me to get model information for hard drives? I'm running CentOS. I want to compare the hard drives on two VPS providers that I use.
5
votes
8answers
1k views

Hard drive partitioning software for Windows

I'm looking for a good disk partitioning/management software suite. I've been using Acronis Disk Director but I've had a few data corruption issues which I think might be related to it (especially ...
5
votes
3answers
4k views

How to stop a linux server from beeping when a RAID HDD has failed

A HDD has just failed on a linux server (Red Hat Linux release 9) we support. Not a big problem since it's on a RAID (MegaRAID SCSI). We're now in the process of getting a new one to replace it. In ...
5
votes
7answers
3k views

What is faster? A local mechical hard drive or a solid state drive over gigabit ethernet?

SSDs are rather new, so I couldn't find this information on the Internet. Would the performance of a local hard drive connected using SATA2 get out performed by a SSD over gigabit ethernet? In terms ...
5
votes
2answers
2k views

How to know which disk has failed on a Mirrored Raid? marked as DR0

Our 2ndry DC, which is on a W2K8R2 Mirrored software raid has lost it's sync, and disk management displays the failed redundancy error How do I know which of the disks has failed? (beside to try ...
5
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 ...
5
votes
4answers
2k views

What is the difference between SAN Hard Drives and Normal Hard Drives?

At work, we have decided to finally virtualize and have decided to upgrade out SAN setup with higher capacity Hard Drives. However, what exactly is the difference between Hard Drives that come ...
5
votes
1answer
1k views

iotop and iostat disagree

I'm trying to understand what's going on with my server's disks. It's running Ubuntu 12.04LTS and I'm used to using iostat to know when the disk is the bottleneck. But iostat -xd looks to me like ...
5
votes
2answers
185 views

raid controller data transfer rate

I'm going to buy an 8-port raid controller for which the declared data trasfer rate is "Up to 6Gb/s per port". The declared connectors are "Two mini-SAS SFF8088". The maximum number of supported ...
5
votes
1answer
285 views

Is it possible to calculate where is, physically, a bad block located on a hard disk?

I dd_rescue'd a hard drive, and I know where the bad blocks are. I still have the drive with me, so I can get any information needed from SMART or fdisk. I would like to know if it is possible to ...
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 ...
5
votes
3answers
4k views

Is it safe to transfer RAID 5 disks from one server to another?

I have (what I assume) will be a relatively simple question. I have an old file server that I've decommissioned and replaced. I would like to re-use the hardware from the old file server at our ...
5
votes
3answers
6k views

How to determine disc spindown time

I am able to set both APM and spindown times using the command: hdparm -S 246 -B 128 /dev/sda Unfortunately I can only find the APM value in the information output: hdparm -I /dev/sda | grep ...
5
votes
3answers
3k views

When to use Truecrypt, and when not to?

I have about 30 (this number will most likely grow over the next few years to 50 or more) unencrypted laptops that I have been tasked to encrypt (entire drive). These machines will be used off site ...
5
votes
5answers
653 views

Unix command to suspend a job while there is console activity?

I want to do a large disk transfer, which slows down responsiveness of my system. What I want is a Unix command that will only run the command after I have been idle at the console for a few minutes. ...
5
votes
2answers
10k views

What is QSignoff?

The QSignoff folder uses a lot of disk space, can is be pared down without issue?
5
votes
2answers
12k views

How do I recover from a faulted zpool where one device is OK, but was temporarily offline?

I have a zpool with 4 2TB USB disks in a raidz config: [root@chef /mnt/Chef]# zpool status farcryz1 pool: farcryz1 state: ONLINE scrub: none requested config: NAME STATE READ ...
5
votes
4answers
3k views

Does virtual hard disk fragmentation reported by a guest machine matter?

We have a VM Ware ESXi virtual machine, where the guest is reporting high fragmentation. The host virtual machine file is not fragmented. The datastore is on a RAID 5 array. Does the fragmentation of ...
5
votes
4answers
5k views

Which FileSystem is best for CentOS 5 on SSD?

Background: We have gigs of data, which require to process large files simultaneously and in parallel with similar processes. We are going to get SSD just because of fastest latency. We will install ...
5
votes
4answers
5k views

How much impact does hard drive cache have on IO performance

How much impact does hard drive cache have on IO performance Are there any statistics or performance tests available that can tell me if there is a difference is 16MB vs 32MB Cache? If it matters, I ...
5
votes
2answers
10k views

How can I set the disk partition alignment using linux tools?

After reading Disk Partition Alignment Best Practices for SQL Server, I just want to give those advices a try, but on my linux test server. What are the required parameters in order to set the ...
5
votes
3answers
163 views

Shared Disk in modern data center (SAN, virtualization, etc)

I'm a developer...treading here on foreign terrain. Please pardon any naivete. I work on an application that stores data both in a database and the filesystem. Context: Clustering and Network ...
5
votes
1answer
492 views

Corrupt files' contents, while FS is OK

Looks like my USB HDD is old and corrupted: rsync: read errors mapping "path/to/file.jpg": Input/output error (5) Syslog: kernel: [58927.940676] sd 6:0:0:0: [sdb] Unhandled sense code kernel: ...
5
votes
3answers
4k views

Is it wise to use SSHDs (Solid state hybrid drives) on a server?

I have a bunch of servers with very heavy I/O that currently use SATA3/SAS drives, but do suffer from I/O wait on the SATA drives, and I have just been alerted to the existence of SSHDs which cost the ...
5
votes
3answers
3k views

PostgreSQL slow commit performance

We are having some problems with a PostgreSQL configuration. After some benchmarks I found out that very simple queries are taking a relatively long time, upon furter inspection it appears that the ...