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13

It would help if you posted your my.cnf and whether you are using InnoDB or MyISAM tables and whether you are a read-heavy or write-heavy workload. Otherwise, we are just making guesses. Here are mine: First, I would look and make sure that your queries are properly indexed. High I/O on MySQL databases is either caused by extremely high concurrency, a ...


7

To add to the answer and to answer the comment (which is a bit too long to answer in a comment) You can try thinking from the very big picture. Will reading from 2 disks be faster than 1? And the obvious answer is yes. If one disk is only capable of reading 100MBps, two disks naturally can read at 200MBps. And that's why the theoretical read speed of raid 0 ...


5

The key thing to remember is that data is distributed in chunks, not per bit or per byte. The chunk size (aka stripe size) varies based on implementation, and is often configurable. The chunk size is typically somewhere between 32KB - 2M. So for a single read request of a file smaller then a single chunk, only a single member of the array will need to be ...


5

Yes, this is possible. See: Can I convert a 1 disk RAID 0 to RAID 1? You're lucky that your striped array has worked until now. The process you'll go through is an "array transformation". Make sure your system has a battery-backed cache (BBWC) on the RAID controller. Add two more disks of equal or greater size than the existing disks. Install the HP ...


5

First of all: to those, who still believes in "RAID0 has no hot spare". It could have a manual spare, done by human, who understand RAID levels and mdadm. mdadm is software RAID, so it could do a lot of interesting things. Credits to Zoredache for the idea! So, the situation: you have RAID0 array of two disks you would like to replace one of them without ...


4

Depending on what controller you use it may be utilizing your built in CPU, so the more disks you add the more CPU will be used when doing huge transfers. So your CPU might indeed be your bottleneck. Apart from that:


3

In the case of this implementation (the LSI SAS2208 controller), JBOD does not use on-board cache, single disk RAID0 uses on-board write-back cache. The ceph benchmark explains it in the test setup. The performance increase comes from caching not striping. Most RAID controllers allow you to setup single disk RAID0 or RAID1 as a way to support JBOD, this ...


3

Based on what you've posted so far my guess is that your striped volume is almost certainly being hampered by slower drives (I see one 6Gb/sec link and 3 3Gb/sec links - I'm willing to bet the 3Gb/sec drives also have lower general operating specs. Like @MikeyB said run speed tests for each disk individually - this will confirm my theory (or send you ...


3

Basically you're going to be using the DISKPART command, but you're going to have to figure out the exact details yourself.


3

If the device is there at /mnt/md0 or wherever then dd will work, to backup to a file use: dd if=/dev/md0 of=/tmp/raid1.img the output can be another device: dd if=/dev/md0 of=/dev/sdb


3

Assuming your SATA card has enough ports then you can add it outside the RAID. Oh and don't mix disk types in RAIDs - bad idea, bad ;)


3

Are you paying for provisioned IOPS? If not, you'll be getting around 100 IOPS per EBS on average, which ties in with what you're seeing with 8 EBS volumes tied together. From here: Standard volumes offer storage for applications with moderate or bursty I/O requirements. Standard volumes deliver approximately 100 IOPS on average with a best effort ...


2

Yes, it can be done (depending on the controller). You may need the "HP Smart Array Advanced Pack" ($$). HP calls RAID1->0 "mirror splitting." Smart Array Advanced Pack is hosted on the Smart Array Controller hardware and can be enabled on the HP Smart Array P212, P410, P410i, and P411 controllers with a Battery Backed Write Cache module or a ...


2

First, many hardware RAID solutions (and all software RAID I know about) will let you add a single disk beside an existing set. You can think of a single disk as a one disk RAID0. Whether or not you can add a disk to a RAID0 set depends on the RAID implementation. An individual hardware RAID card may not let you do it, some might. As for mixing and ...


2

First of all, I recommend that you create another copy of your HD drives. This is necessary to avoid data loss in case you made a mistake while trying to fix your raid. You can use the following command to create the raid1 array: $ sudo mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1 Of course, you can customize the above command ...


2

Well, first off, I'm not a big fan of spinrite.. (just my opinion, I know others seem to love it) Second, go find your backup (you do have backups, right?) Third, you can look at drive recovery services if you really need the data.


2

XFS is not a RAID implementation. It is a filesystem. It does happen to have some nice tweaking ability. Some of those tweaks increase the performance of the filesystem when used in a RAID array. It is very fast...especially when configured properly. That's probably why Amazon recommends it.


2

Most decently modern raid controllers won't care what physical slots the drives are in; the RAID config is stored on the drives themselves. What you'll want to do is to insert one pair into one of the systems, and boot into the RAID config tool with a key combination at boot. If the RAID cards in those Dells are the standard PERC cards, they'll either ...


2

I'm also not sure why you would want to mix HW and SW RAID, though I do understand your paranoia. I also understand your limitations in terms of backup, so here are my suggestions. Mixing RAIDs is probably not a good idea, and I would personally not trust a Windows RAID a whole lot. For example, Win2k8 seems to have some limitations with alerting you when ...


2

You're not going to be able to do this online, because RAID-0 is completely incapable of handling failures, and the md system depends on failures to trigger rebuilds onto spare components. There is no way to say "can you please use this device instead of that device" without saying "that device has failed" -- which, of course, is going to give your RAID-0 ...


2

There are a variety of tools that you can use. dd is probably as good as many. Clonezilla is a good tool, there are more on this wikipedia page too.


2

This is a problem many, many companies have run into, and solutions to it are fairly well-discussed on various online forums. Typically to increase the potential iops, two or more EBS volumes are joined together in a RAID0 array. This doesn't come without risk, though. As you know, with RAID0, all it takes is for one of the member EBS volumes to have an ...


2

is it safe to use RAID0 with LVM and XFS? In general, yes. is it safe to use xfs_grow to increase storage while the files in the file system are being written into? Yes, this is how it is intended to be used. That said, I have posted questions in the comments above about the specifics of what you are trying to do as it sounds a bit strange.


2

You're not really giving us enough information to go off of. Taking any kind of write penalty out of the equation if we assume your using standard 7200rpm Sata drives then your IOPS would be as follows: 1/(12ms seek time (.012)+ 5.5ms latency (.0055))= 57.14 IOPS So we would use the following to determine the IOPS of the array: 8 (numdisks)* 57.14 ...


2

You should check your raid controller to see what the status is of the hard drives. If your green on all you should then go into disk management and check to see if the disks show. If they are there but show as foreign or inactive you'll need to either import them back or set them to active.


2

Bad block check must be done in the disk device itself, since you are using mdadm RAID you should stop the array and run checks on /dev/sda2 and /dev/sdb2. But before doing this, if you value your data I do recommend a backup, the possibility of losing the entire RAID-0 array exists.


2

It looks like that is a custom build server. I presume the perc 6/i is on the motherboard. Assuming you have an appropriate pci-e slot available, I would just add a SATA controller HBA (one which can operate in IT mode, not a "Raid" one), and connect it to the backplane. I like LSI controllers and have been using the 9207-8i - I'm doing SAS (however they ...


1

Backup and restore is the only possible solution.


1

3- Do you believe such scenario is heavily impacting our apps? Would they perform much better in case we move to a RAID 0 and/or cluster solution? Since you are running an SQL server, it would make more sense to take a look at the SQL server metrics instead to know if queries are served quickly. Looking at your single-digit average request wait times ...


1

Since 500gps is a fairly mild load on the sql server i suggest looking at the percentage of temp tables created on disk and start optimizing your queries and MySQL Server Settings. 1, Do not do the Raid0 approach, it will eventually fail and you will regret it. 2, No, at this low number of queries per second you do not need MySQL Cluster. 3, Yes, it ...



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