Primarily questions about disk storage, sometimes questions about application storage or cloud storage. Always questions about storing data.

learn more… | top users | synonyms

111
votes
2answers
17k views

What are the different widely used RAID levels and when should I consider them?

This is a Canonical Question about RAID levels. What are: the RAID levels typically used (including the RAID-Z family)? deployments are they commonly found in? benefits and pitfalls of each? ...
10
votes
4answers
16k views

Incredibly low disk performance on HP ProLiant DL385 G7

As a test of the Opteron processor family, I bought a HP DL385 G7 6128 with HP Smart Array P410i Controller - no memory. The machine has 20GB ram 2x146GB 15k rpm SAS + 2x250GB SATA2, both in Raid 1 ...
16
votes
1answer
9k views

Hosting a ZFS server as a virtual guest

I'm still new to ZFS. I've been using Nexenta but I'm thinking of switching to OpenIndiana or Solaris 11 Express. Right now, I'm at a point of considering virtualizing the ZFS server as a guest within ...
123
votes
6answers
13k views

Are SSD drives as reliable as mechanical drives (2013)?

SSD drives have been around for several years now. But the issue of reliability still comes up. I guess this is a follow up from this question posted 4 years ago, and last updated in 2011. It's now ...
79
votes
6answers
16k views

Why is Enterprise Storage so expensive?

This is a Canonical Question about the Cost of Enterprise Storage. See also the following question: What's the best way to explain storage issues to developers and other users ...
23
votes
3answers
9k views

Linux - real-world hardware RAID controller tuning (scsi and cciss)

Most of the Linux systems I manage feature hardware RAID controllers (mostly HP Smart Array). They're all running RHEL or CentOS. I'm looking for real-world tunables to help optimize performance for ...
8
votes
1answer
8k views

How exactly does a SAS SFF-8087 breakout cable work? + RAID/connection questions

Please let me know if my question does not makes any sense as I am not sure if I am interpreting it correctly from my thoughts due to my lack of technical knowledge on this. If I am using a ...
36
votes
20answers
17k views

Storing a million images in the filesystem

I have a project that will generate a huge number of images. Around 1,000,000 for start. They are not large images so I will store them all on one machine at start. How do you recommended on ...
25
votes
5answers
34k views

What is the difference between SAN, NAS and DAS?

What is the difference between SAN, NAS and DAS?
43
votes
7answers
5k views

Probability of Blade Chassis Failure

In my organisation we are thinking about buying blade servers - instead of rack servers. Of course technology vendors also make them sound very nice. A concern, that I read very often in different ...
4
votes
4answers
17k views

Disabling RAID feature on HP Smart Array P400

I'm planning to use ZFS on my system (HP ML370 G5, Smart Array P400, 8 SAS disk). I want ZFS to manage all disks individually, so it can utilize better scheduling (i.e. I want to use software RAID ...
54
votes
13answers
78k views

Windows 2008: WinSXS directory growing uncontrollably, blocking server

I run a (remotely hosted) virtual Server with Windows 2008 Server for a client. Initially, it had 10 GB of space. During the course of a few weeks - during which nothing was done on the machine ...
42
votes
3answers
48k views

What are the merits of SAS vs SATA drives? [closed]

What are the merits of buying SAS drives over SATA drives, or vice versa?
19
votes
2answers
3k views

ZFS Data Loss Scenarios

I'm looking toward building a largish ZFS Pool (150TB+), and I'd like to hear people experiences about data loss scenarios due to failed hardware, in particular, distinguishing between instances where ...
3
votes
1answer
5k views

RAID5 on SmartArray P410i online resize

I have P410i+256M Cache without battery backup. My RAID5 was build over 3*136GB disks, now all disks were replaced to a 3*300GB array. How can I extend it to use the whole space? HPacucli doesn't ...
29
votes
2answers
7k 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. ...
9
votes
10answers
11k views

Which Distributed File System as a backend for Cloud Computing?

I have a basic cloud running on Ubuntu Server (9.04) and Eucalyptus. Walrus (Eucalyptus' API compatable S3 implementation) stores files by on the cloud controller. However each of the other 4 server ...
10
votes
1answer
4k views

Is calculating IOPS for ZFS RAIDZ different then calculating IOPS for RAID5 & RAID6?

When calculating IOPS for traditional RAID arrays, one could use the following formula (Borrowed from Getting The Hang Of IOPS v1.3 on Symantec Connect): Ieffective = (n * Isingle) / (READ% + (F * ...
5
votes
6answers
6k views

Is there a way to do something like LVM over NFS?

I realize that since NFS is not block-level, LVM can't be used directly. However: is there a way to combine multiple NFS exports (from, say, 3 servers) into one mount point on a different server? ...
29
votes
10answers
24k views

Cheapest way to connect 20-24 Sata II HDDs in a budget storage server? [closed]

I need to assemble a high density storage server for as cheap as possible. It's been a while for me and the last systems I integrated didn't even have Sata yet... During my Research I of course ...
6
votes
8answers
2k views

What are SAS external storage options (Promise, Infortrend, SuperMircro, …)?

We are looking for a ~32T external storage solution for two 48-core AMD servers. These will be used for a small Linux OpenVZ cloud for CPU intensive web-servers and data warehousing. Dual path with ...
6
votes
5answers
16k views

How do I get my HP servers to email me when a drive fails?

Ideally, with as simple of install as possible and without requiring rebooting the servers. Mostly for DL380 G5's if it helps. Thanks.
26
votes
5answers
3k views

Do I need to RAID Fusion-io cards?

Can I run reliably with a single Fusion-io card installed in a server, or do I need to deploy two cards in a software RAID setup? Fusion-io isn't very clear (almost misleading) on the topic when ...
10
votes
3answers
9k views

Battery Backed Write Cache

I recently got some U server price quotes and some of them include BBWC: What exactly does it do? Is it just for RAID configurations? If there is a power malfunction, isn't the data loss ...
8
votes
2answers
3k views

CentOS 6 doing lots more IO than CentOS 5

I'm benchmarking an application on two identical servers, one is Centos 5.8 and the other is Centos 6.2. My application is running much slower (50% or less) on the Centos 6.2 machine. In attempting ...
7
votes
3answers
639 views

What is the use-case for NAS on a mid-to-high end storage array?

Many large storage vendors (EMC, NetApp, etc) provide storage equipment that does NAS in addition to FCP, FCoE, or iSCSI. When would it be appropriate to use the NAS functionality of these boxes? In ...
9
votes
2answers
713 views

/home/vhosts/ or /var/www/

Some web servers I've come across use /home to store the site files: /home/vhosts/www.example.com/ Others use /var like: /var/www/www.example.com/ What's more clean and "Linuxy"? Should we all ...
4
votes
2answers
865 views

6 Disk Raid 1+0

I have an HP Smart Array P400i raid controller, with 6 disks, working in a RAID 1+0. This is what it looks like: Mirror Group 0: physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 72 GB, ...
4
votes
2answers
1k views

SAS enclosure doesn't restart - MSA60

I just inherited a HP StorageWorks MSA60 (this is a direct-attach SAS enclosure). I had to move it to another shelf so I turned off the computer which was using it. I also pulled the 2 power cords off ...
1
vote
3answers
2k views

HP DL585 G1 with VMware ESXi 5 - SATA solution, need more storage

I have the following: 2 x DL585 G1 (8 cores) with built in Smart Array 5i (2 x 74GB SCSI in Raid 0) I installed VMware ESXi 5 and got it all working :) However I need more space. I was thinking ...
35
votes
8answers
2k views

What's the best way to explain storage issues to developers and other users

When server storage gets low developers all start to moan, "I can get a 1 TB drive at Walmart for 100 bucks, what's the problem". How can the complexities of storage be explained to developers so ...
40
votes
8answers
8k views

Is it safe to use consumer MLC SSDs in a server?

We (and by we I mean Jeff) are looking into the possibility of using Consumer MLC SSD disks in our backup data center. We want to try to keep costs down and usable space up - so the Intel X25-E's ...
8
votes
8answers
9k views

Home-brew automatic tiered storage solutions with Linux? (Memory -> SSD -> HDD -> remote storage)

Related to this question about using an SSD for system and HDD for data, except I would like my system to do this automatically... Is it possible to have several layers of storage and push items ...
17
votes
3answers
4k views

How effective is LSI CacheCade SSD storage tiering?

LSI offers their CacheCade storage tiering technology, which allows SSD devices to be used as read and write caches to augment traditional RAID arrays. Other vendors have adopted similar ...
32
votes
11answers
11k views

Does an unplugged hard drive used for data archival deteriorate?

If I were to archive data on a hard drive, unplug it, and set it on a (not dusty, temperature-controlled) shelf somewhere, would that drive deteriorate much? How does the data retention of an ...
6
votes
2answers
3k views

Can I determine IOPS on a disk array using bonnie++?

I would like to measure the read and write performance of a RAID6 array verses a RAID10 array. I understand that bonnie++ can be used to calculate disk performance, but the numbers produced by ...
19
votes
5answers
2k views

BBWC: in theory a good idea but has one ever saved your data?

I'm familiar with what a BBWC (Battery-backed write cache) is intended to do - and previously used them in my servers even with good UPS. There are obvously failures it does not provide protection ...
10
votes
3answers
1k views

HP storage arrays - multiple channels?

Our SQL server is becoming pretty heavily loaded, and all indications point to the disk channel being the bottleneck. The current HP server has a fairly low-end array card, and we're looking to ...
6
votes
1answer
11k views

KVM guest io is much slower than host io: is that normal?

I have a Qemu-KVM host system setup on CentOS 6.3. Four 1TB SATA HDDs working in Software RAID10. Guest CentOS 6.3 is installed on separate LVM. People say that they see guest performance almost equal ...
1
vote
4answers
18k views

How can I un-mark a partition as active?

Overview: I use a backup storage enclosure with 6 backup drives incrementally backup up and taken off-site. One day I noticed that the backup process was failing. I logged onto the server that is ...
10
votes
2answers
4k views

What is ephemeral storage good for?

I have been reading about the ephemeral storage with amazon ec2 and am trying to figure out what is the best way to use the 100s of GBs they supply you. If it isn't persistent, what can it be good ...
9
votes
3answers
30k views

SAS vs. Nearline/MDL SAS - What is the difference?

As subject I guess, looking at SAN's and most vendors offer 10k or 15k "proper" SAS drives, many also offer 7.2k MDL/Nearline SAS drives. Does anyone have an authoritative explanation of the ...
1
vote
4answers
255 views

file share system architecture asking for advice

I am using Windows platform to setup a web based file share system. In more details, individual users could upload and share documents from web interface (content may be big document, like video ...
0
votes
3answers
2k views

3WARE 9650-4LPML JBOD DISK to RAID - 1 Mirror Migration How To?

It is possible to migrate a single disk, to Raid 1 as per Table 10 in the User Guide Page 122: http://www.3ware.com/support/UserDocs/3ware9650SE-UsrGuide.pdf I am trying to find what the best method ...
2
votes
4answers
2k views

multiple file systems for mysql

Does mysql support multiple file systems for a single database with most of the tables being on MyISAM? Context: we have a 1.5TB mysql database, which is increasing at the rate of 200GB per month. ...
0
votes
2answers
4k views

HP ACU shows parity initialization failed on Smart Array controller

I put in a new drive due to a hard drive failure. When the rebuild got to 100%, the controller fails and I need to reboot the server to bring it online. I had to do this about three times and it ...
0
votes
3answers
905 views

dell 2T 7.2k nearline SAS 6Gbps- ingress/egress throughput

I would like to know, how to calculate sustained read and write speeds supported. I don't have access to machine/drive, but need to define specs to purchase one. What all things would it be ...
36
votes
12answers
25k views

ZFS vs XFS

We're considering building a ~16TB storage server. At the moment, we're considering both ZFS and XFS as filesystem. What are the advantages, disadvantages? What do we have to look for? Is there a ...
29
votes
2answers
3k views

What is a Storage Area Network, and which benefits does it have over different storage solutions?

I'm proposing this to be a canonical question about enterprise-level Storage Area Networks. What is a Storage Area Network (SAN), and how does it work? How is it different from a Network Attached ...
18
votes
10answers
10k views

Distributed Storage Filesystem - Which one/Is there a ready to use product?

With Hadoop and CouchDB all over in Blogs and related news what's a distributed-fault-tolerant storage (engine) that actually works. CouchDB doesn't actually have any distribution features built-in, ...