Re: What will happen after adding another data disk
JBOD before 3.6 or so mixed data between disks in a way that if one disk failed, you needed to treat them all as failed and replace the host -- Jeff Jirsa > On Jun 12, 2018, at 1:53 AM, Kyrylo Lebediev wrote: > > Also it worth noting, that usage of JBOD isn't recommended for older > Cassandra versions, as there are known issues with data imbalance on JBOD. > iirc JBOD data imbalance was fixed in some 3.x version (3.2?) > For older versions creation one large filesystem on top md or lvm device > seems to be a better choice. > > From: Eunsu Kim > Sent: Tuesday, June 12, 2018 9:06:07 AM > To: user@cassandra.apache.org > Subject: Re: What will happen after adding another data disk > > In my experience, adding a new disk and restarting the Cassandra process > slowly distributes the disk usage evenly, so that existing disks have less > disk usage > >> On 12 Jun 2018, at 11:09 AM, wxn...@zjqunshuo.com wrote: >> >> Hi, >> I know Cassandra can make use of multiple disks. My data disk is almost full >> and I want to add another 2TB disk. I don't know what will happen after the >> addition. >> 1. C* will write to both disks util the old disk is full? >> 2. And what will happen after the old one is full? Will C* stop writing to >> the old one and only writing to the new one with free space? >> >> Thanks! >
Re: What will happen after adding another data disk
Thank you all. I don't know if my case is the situation mentioned by JBOD. My cluster is on Aliyun Cloud and the Cassandra version is 2.2.8. Data imbalance is not a problem for me if whenever memtable is flushing to sstable, and Cassandra can choose a disk with sufficient free space. Thanks, -Simon From: Kyrylo Lebediev Date: 2018-06-12 16:53 To: user@cassandra.apache.org Subject: Re: What will happen after adding another data disk Also it worth noting, that usage of JBOD isn't recommended for older Cassandra versions, as there are known issues with data imbalance on JBOD. iirc JBOD data imbalance was fixed in some 3.x version (3.2?) For older versions creation one large filesystem on top md or lvm device seems to be a better choice. From: Eunsu Kim Sent: Tuesday, June 12, 2018 9:06:07 AM To: user@cassandra.apache.org Subject: Re: What will happen after adding another data disk In my experience, adding a new disk and restarting the Cassandra process slowly distributes the disk usage evenly, so that existing disks have less disk usage On 12 Jun 2018, at 11:09 AM, wxn...@zjqunshuo.com wrote: Hi, I know Cassandra can make use of multiple disks. My data disk is almost full and I want to add another 2TB disk. I don't know what will happen after the addition. 1. C* will write to both disks util the old disk is full? 2. And what will happen after the old one is full? Will C* stop writing to the old one and only writing to the new one with free space? Thanks!
Re: What will happen after adding another data disk
Also it worth noting, that usage of JBOD isn't recommended for older Cassandra versions, as there are known issues with data imbalance on JBOD. iirc JBOD data imbalance was fixed in some 3.x version (3.2?) For older versions creation one large filesystem on top md or lvm device seems to be a better choice. From: Eunsu Kim Sent: Tuesday, June 12, 2018 9:06:07 AM To: user@cassandra.apache.org Subject: Re: What will happen after adding another data disk In my experience, adding a new disk and restarting the Cassandra process slowly distributes the disk usage evenly, so that existing disks have less disk usage On 12 Jun 2018, at 11:09 AM, wxn...@zjqunshuo.com<mailto:wxn...@zjqunshuo.com> wrote: Hi, I know Cassandra can make use of multiple disks. My data disk is almost full and I want to add another 2TB disk. I don't know what will happen after the addition. 1. C* will write to both disks util the old disk is full? 2. And what will happen after the old one is full? Will C* stop writing to the old one and only writing to the new one with free space? Thanks!
Re: What will happen after adding another data disk
In my experience, adding a new disk and restarting the Cassandra process slowly distributes the disk usage evenly, so that existing disks have less disk usage > On 12 Jun 2018, at 11:09 AM, wxn...@zjqunshuo.com wrote: > > Hi, > I know Cassandra can make use of multiple disks. My data disk is almost full > and I want to add another 2TB disk. I don't know what will happen after the > addition. > 1. C* will write to both disks util the old disk is full? > 2. And what will happen after the old one is full? Will C* stop writing to > the old one and only writing to the new one with free space? > > Thanks!
